Gun Owners of America, Inc. v. Merrick B. Garland

RECOMMENDED FOR PUBLICATION
Pursuant to Sixth Circuit I.O.P. 32.1(b)
File Name: 21a0070p.06

UNITED STATES COURT OF APPEALS
FOR THE SIXTH CIRCUIT

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GUN OWNERS OF AMERICA, INC.; GUN OWNERS
│
FOUNDATION; VIRGINIA CITIZENS DEFENSE LEAGUE;
│
MATT WATKINS; TIM HARMSEN; RACHEL MALONE,
│
Plaintiffs-Appellants, │
> No. 19-1298
│
GUN OWNERS OF CALIFORNIA, INC., │
Movant, │
│
v. │
│
│
MERRICK B. GARLAND, in his official capacity as │
Attorney General of the United States; UNITED STATES │
DEPARTMENT OF JUSTICE; BUREAU OF ALCOHOL, │
TOBACCO, FIREARMS AND EXPLOSIVES; REGINA │
LOMBARDO, in her official capacity as Acting │
Director, Bureau of Alcohol, Tobacco, Firearms, and │
Explosives, │
Defendants-Appellees. │
┘

Appeal from the United States District Court
for the Western District of Michigan at Grand Rapids.
No. 1:18-cv-01429—Paul Lewis Maloney, District Judge.

Argued: December 11, 2019

Decided and Filed: March 25, 2021

Before: BATCHELDER, WHITE, and MURPHY, Circuit Judges.

_________________

COUNSEL

ARGUED: Robert J. Olson, WILLIAM J. OLSON, P.C., Vienna, Virginia, for Appellants.
Brad Hinshelwood, UNITED STATES DEPARTMENT OF JUSTICE, Washington, D.C., for
Appellees. ON BRIEF: Robert J. Olson, WILLIAM J. OLSON, P.C., Vienna, Virginia, Kerry
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 2

L. Morgan, PENTIUK, COUVREUR & KOBILJAK, P.C., Wyandotte, Michigan, for
Appellants. Brad Hinshelwood, Abby C. Wright, UNITED STATES DEPARTMENT OF
JUSTICE, Washington, D.C., for Appellees. Ilya Shapiro, CATO INSTITUTE, Washington,
D.C., James Bardwell, NATIONAL ASSOCIATION FOR GUN RIGHTS, Loveland, Colorado,
for Amici Curiae.

BATCHELDER, J., delivered the opinion of the court in which MURPHY, J., joined.
WHITE, J. (pp. 38–60), delivered a separate dissenting opinion.
_________________

OPINION
_________________

ALICE M. BATCHELDER, Circuit Judge. The question before us is whether a bump
stock may be properly classified as a machine gun as defined by 26 U.S.C. § 5845(b).1 But this
case rests as much on who determines the statute’s meaning as it does on what the statute means.

On December 26, 2018, the Bureau of Alcohol, Tobacco, Firearms, and Explosives
(“ATF” or “Agency”) promulgated a rule that classified bump stocks as machine guns, reversing
its previous position. See Bump-Stock-Type Devices, 83 Fed. Reg. 66,514 (Dec. 26, 2018) (to
be codified at 27 C.F.R. pts. 447, 478, 479) (“Final Rule”). Plaintiffs-Appellants—three gun-
rights organizations, two individuals who own bump stocks, and one individual who would
purchase a bump stock if not for the Final Rule—filed a motion for a preliminary injunction to
prevent the Final Rule from taking effect. After finding that the ATF’s interpretation was
entitled to Chevron deference, the district court held that the Final Rule’s classification of bump
stocks as machine guns was “a permissible interpretation” of § 5845(b). Accordingly, the court
concluded that Plaintiffs-Appellants were unlikely to succeed on the merits and denied the
preliminary injunction.

Because an agency’s interpretation of a criminal statute is not entitled to Chevron
deference and because the ATF’s Final Rule is not the best interpretation of § 5845(b), we
REVERSE the district court’s judgment and REMAND for proceedings consistent with this
opinion.

1We will use the modern spelling of “machine gun” as two words unless quoting 26 U.S.C. § 5845(b),
which spells “machinegun” as one word.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 3

I. Background

A. Statutory History of the Machine Gun

For as long as there have been firearms, there have been efforts to make them shoot
faster. See JOHN ELLIS, THE SOCIAL HISTORY OF THE MACHINE GUN 9-14 (1986). The modern-
day machine gun dates back to the nineteenth century with Richard Gatling’s 1861 invention of
the hand-cranked Gatling gun and Hiram Maxim’s 1884 invention of the fully automatic Maxim
gun. At first, these technological advances changed only the nature of warfare. But their impact
soon reached the civilian world with the submachine gun becoming the weapon of choice of
organized crime during the Prohibition Era. See David T. Hardy, The Firearms Owners’
Protection Act: A Historical and Legal Perspective, 17 CUMB. L. REV. 585, 589-90 (1987).

Seeking to crack down on the criminal use of concealable, high-powered firearms,
Congress passed the National Firearms Act of 1934, Pub. L. No. 73-474, 48 Stat. 1236 (codified
as amended in I.R.C. ch. 53). See S. REP. NO. 73-1444, at 1-2 (1934) (“The gangster as a law
violator must be deprived of his most dangerous weapon, the machine gun. Your committee is
of the opinion that limiting the bill to the taxing of sawed-off guns and machine guns is sufficient
at this time.”). “Representing the first major federal attempt to regulate firearms,” that 1934 Act
levied a then-steep $200 tax (estimated at over $3,800 in today’s dollars) on the purchase of a
machine gun. Lomont v. O’Neill, 285 F.3d 9, 11-12 (D.C. Cir. 2002); Ch. 757, 48 Stat. at 1237;
see also National Firearms Act: Hearings on H.R. 9066 Before the H. Comm. on Ways and
Means, 73d Cong. 22-24 (1934) (Attorney General Homer Cummings explaining to the House
Ways and Means Committee that the tax provision would permit the federal government to
successfully prosecute gangsters with tax evasion, as it had done with Al Capone). That 1934
Act defined “machine gun”:

The term “machine gun” means any weapon which shoots, or is designed to
shoot, automatically or semiautomatically, more than one shot, without manual
reloading, by a single function of the trigger.

Ch. 757, 48 Stat. at 1236.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 4

Thirty years later, in response to several high-profile assassinations, including those of
President John F. Kennedy, Senator Robert F. Kennedy, and Dr. Martin Luther King, Jr.,
Congress passed the Gun Control Act of 1968, which, among other restrictions, prohibited
felons, drug users, and the mentally ill from purchasing firearms. Pub. L. No. 90-618, 82 Stat.
1213 (amending 18 U.S.C. §§ 921-28 and I.R.C. ch. 53). The 1968 Act’s definition of a machine
gun largely adopted the 1934 Act’s definition but also expanded its scope to include other parts
or devices that could convert a weapon into a machine gun:

The term “machinegun” means any weapon which shoots, is designed to shoot, or
can be readily restored to shoot, automatically more than one shot, without
manual reloading, by a single function of the trigger. The term shall also include
the frame or receiver of any such weapon, any combination of parts designed and
intended for use in converting a weapon into a machinegun, and any combination
of parts from which a machinegun can be assembled if such parts are in the
possession or under the control of a person.

§ 5845(b), 82 Stat. at 1231.

Finally, in 1986, Congress passed the Firearm Owners’ Protection Act, which banned
civilian ownership of machine guns manufactured after May 1986, as well as any parts used to
convert an otherwise legal semiautomatic firearm into an illegal machine gun. Pub. L. No. 99-
308, 100 Stat. 449 (1986) (amending 18 U.S.C. §§ 921-29). The 1986 Act amended only the
second part of § 5845(b):

Section 5845(b) of the National Firearms Act (26 U.S.C. 5845(b)) is amended by
striking out “any combination of parts designed and intended for use in converting
a weapon into a machinegun,” and inserting in lieu thereof “any part designed and
intended solely and exclusively, or combination of parts designed and intended,
for use in converting a weapon into a machinegun.”

§ 109(a), 100 Stat. at 460.

Thus, as currently codified, the statutory definition of a machine gun reads:

The term “machinegun” means any weapon which shoots, is designed to shoot, or
can be readily restored to shoot, automatically more than one shot, without
manual reloading, by a single function of the trigger. The term shall also include
the frame or receiver of any such weapon, any part designed and intended solely
and exclusively, or combination of parts designed and intended, for use in
converting a weapon into a machinegun, and any combination of parts from
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 5

which a machinegun can be assembled if such parts are in the possession or under
the control of a person.

26 U.S.C. § 5845(b) (2019).

While Congress has enacted other legislation during the past 30 years, both expanding
and reducing gun-control measures, no law has amended the definition of a machine gun since
1986.

B. Regulatory History of the Bump Stock

Though there are different versions, all bump stocks are devices designed to assist the
shooter in “bump firing,” a technique that increases a semiautomatic firearm’s rate of fire. The
bump stock replaces the standard stock of a semiautomatic rifle, i.e., the end of the rifle that rests
against the shooter’s shoulder. In contrast to the standard stock, which is stationary, the bump
stock is a sliding stock that enables the firearm to move backwards and forwards in a
“constrained linear”—i.e., straight—fashion. Final Rule, 83 Fed. Reg. at 66,518. To initiate
bump firing, the shooter pulls the trigger once, firing one shot, while maintaining “constant
forward pressure with the non-trigger hand on the barrel-shroud or fore-grip of the rifle.” Id. at
66,516. At the same time, the shooter also maintains constant rearward pressure with his trigger
hand, while keeping his trigger finger stationary. The recoil energy from the fired shot causes
the firearm to slide backward approximately 1.5 inches. Id. at 66,518. The forward pressure
applied by the shooter’s non-trigger hand, along with the recoil energy channeled by the bump
stock, causes the firearm to then slide forward. As the firearm slides forward, the trigger
“bumps” against the shooter’s stationary trigger finger, causing the trigger to depress and the
firearm to shoot again. This second fired shot creates recoil energy once again, which again
causes the bump-stock-attached firearm to slide back. The trigger is released and reset, and the
process repeats.

This cycle will continue until the shooter moves his or her trigger finger, fails to maintain
constant forward pressure with the non-trigger hand, the firearm malfunctions, or the firearm
runs out of ammunition. As with any semiautomatic weapon, the trigger must be completely
depressed, released, and then reset before it is capable of firing another shot. Only one shot is
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 6

fired each time the trigger is depressed. The bump stock enables a shooter to complete this
depress-release-reset cycle of the trigger faster than would otherwise be possible without the
bump stock.

Though the bump-firing technique has been around for as long as there have been
semiautomatic firearms,2 the first patented bump-stock device was invented only 20 years ago.
In 1998, William Akins applied for a patent for an “apparatus for accelerating the cyclic firing
rate of a semi-automatic firearm.” Akins v. United States, No. 8:08-cv-988, 2008 WL 11455059,
at *2 (M.D. Fla. Sept. 23, 2008). Akins received Patent No. 6,101,918 on August 15, 2000, and
named his new device the “Akins Accelerator.” Id. In March 2002, Akins asked the ATF
whether it would classify the Akins Accelerator as a machine gun. Id. After some initial
confusion, the ATF confirmed that the Akins Accelerator “[did] not constitute a machinegun
. . . [nor] a part or parts designed and intended for use in converting a weapon into a
machinegun,” and Akins began to mass produce and distribute his new device. Id.

In 2006, the ATF opened an investigation and, by its own admission, “overruled” its
previous decision that the Akins Accelerator was not a machine gun. Final Rule, 83 Fed. Reg. at
66,517. The Agency concluded that the Accelerator’s internal spring made the device a machine
gun, but stated that if Accelerator owners removed the internal spring from the device, then it
“would render the device a non-machinegun under the statutory definition.” Id. Akins sued,
arguing that the Agency’s reversal was unreasonable, that the reversal violated due process, and
that the statutory definition of machine gun was unconstitutionally vague. See Akins v. United
States, 312 F. App’x 197, 198 (11th Cir. 2009) (per curiam). But his suit failed. Id.

Meanwhile, “[b]etween 2008 and 2017, [the] ATF [] issued classification decisions
concluding that other bump-stock-type devices were not machineguns, primarily because the
devices did not rely on internal springs or similar mechanical parts to channel recoil energy.”
Final Rule, 83 Fed. Reg. at 66,514 (emphasis added). But, as with the Akins Accelerator, the
ATF later reversed course on these nonmechanical bump stocks too.

2A bump stock device is not needed to facilitate bump firing. Final Rule, 83 Fed. Reg. at 66,532-33.
Rubber bands, belt loops, and even shoestrings can all facilitate bump firing and create the same continuous firing
cycle that a bump-stock device creates. Id.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 7

On October 1, 2017, in Las Vegas, Nevada, a gunman from his 32nd-floor hotel room
fired down on a crowd of people at a nearby concert for nearly fifteen minutes, killing 58 and
wounding over 500. The gunman used bump-stock devices attached to his semiautomatic rifles
to increase his rate of firing, allowing him to inflict heavy casualties in a short period of time. In
response to the shooting, President Trump “direct[ed] the Department of Justice to dedicate all
available resources . . . as expeditiously as possible, to propose for notice and comment a rule
banning all devices that turn legal weapons into machineguns.” Application of the Definition of
Machinegun to “Bump Fire” Stocks and Other Similar Devices, 83 Fed. Reg. 7949 (Feb. 23,
2018).

On March 29, 2018, the Department of Justice (“DOJ”) published a notice of proposed
rulemaking that reinterpreted the terms “single function of the trigger” and “automatically,” as
used in 26 U.S.C. § 5845(b), in order to classify bump stocks as machine guns. Bump-Stock-
Type Devices, 83 Fed. Reg. 13,442 (proposed Mar. 29, 2018) (to be codified at 27 C.F.R. pts.
447, 478, 479). Over 186,000 comments were submitted in response to the notice. Final Rule,
83 Fed. Reg. at 66,519. On December 26, 2018, the ATF published the Final Rule, classifying
bump stocks as machine guns. Id. at 66,514. The Final Rule rescinded the ATF’s prior
classification letters permitting nonmechanical bump stocks and held that all bump stocks must
either be surrendered to the government or destroyed by March 26, 2019, in order for bump-
stock owners to avoid criminal liability. Id.

C. Procedural History

Plaintiffs-Appellants filed suit on December 26, 2018, the same day that the Final Rule
was published in the Federal Register. Plaintiffs-Appellants claimed that the Final Rule violated
the Administrative Procedure Act (“APA”), the Fifth Amendment’s Takings Clause, and the
Fourteenth Amendment’s Due Process Clause. Plaintiffs-Appellants also sought a preliminary
injunction to stop the Final Rule from taking effect. The district court denied the preliminary
injunction. Gun Owners of Am. v. Barr, 363 F. Supp. 3d 823, 834 (W.D. Mich. 2019). The court
found that the ATF’s interpretation was entitled to Chevron deference and that the Final Rule’s
classification of bump stocks as machine guns was “a permissible interpretation” of § 5845(b).
Id. at 830-32.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 8

While appealing the denial of their preliminary injunction, Plaintiffs-Appellants moved to
stay the effective date of the Final Rule. We denied the requested stay, Gun Owners of Am., Inc.
v. Barr, No. 19-1298, 2019 WL 1395502, at *1-2 (6th Cir. Mar. 25, 2019), as did the Supreme
Court, Gun Owners of Am., Inc. v. Barr, No. 18A963, 139 S. Ct. 1406 (2019). The Final Rule
took effect on March 26, 2019.

Before us now is Plaintiffs-Appellants’ appeal of the district court’s denial of their
request for a preliminary injunction.

II. Standard of Review

“When deciding whether to issue a preliminary injunction, the district court considers the
following four factors: (1) whether the movant has a ‘strong’ likelihood of success on the merits;
(2) whether the movant would otherwise suffer irreparable injury; (3) whether issuance of a
preliminary injunction would cause substantial harm to others; and (4) whether the public
interest would be served by issuance of a preliminary injunction.” Leary v. Daeschner, 228 F.3d
729, 736 (6th Cir. 2000) (citation omitted). The final two factors—assessing the harm to others
and weighing the public interest—“merge when the Government is the opposing party.” Wilson
v. Williams, 961 F.3d 829, 844 (6th Cir. 2020) (quoting Nken v. Holder, 556 U.S. 418, 435
(2009)).

“When a party appeals the denial of a preliminary injunction, we ask whether the district
court abused its discretion—by, for example, applying an incorrect legal standard, misapplying
the correct one, or relying on clearly erroneous facts.” Pulte Homes, Inc. v. Laborers’ Int’l
Union of N. Am., 648 F.3d 295, 305 (6th Cir. 2011). This means that we “review the district
court’s legal conclusions de novo and its factual determinations for clear error.” Id. “The
district court’s determination of whether the movant is likely to succeed on the merits is a
question of law and is accordingly reviewed de novo.” Certified Restoration Dry Cleaning
Network, LLC v. Tenke Corp., 511 F.3d 535, 541 (6th Cir. 2007).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 9

III. Analysis: Chevron Deference

Before determining whether the ATF’s interpretation of § 5845(b) prevails, we must
determine what deference, if any, we must give to its interpretation. Plaintiffs-Appellants argue
that an agency’s construction is not, or should not be, entitled to deference when construing a
criminal statute.3 We agree and conclude that Chevron deference categorically does not apply to
the judicial interpretation of statutes that criminalize conduct, i.e., that impose criminal penalties.
Because the definition of machine gun in § 5845(b) applies to a machine-gun ban carrying
criminal culpability and penalties, we cannot grant Chevron deference to the ATF’s
interpretation.

A. Chevron Deference

In what turned out to be a landmark decision, Chevron USA, Inc. v. Natural Resources
Defense Council, Inc., 467 U.S. 837, 865 (1984), introduced the concept of “Chevron
deference”: an administering agency’s interpretation of a statute “is entitled to deference” from
the courts. “Chevron is rooted in a background presumption of congressional intent,” that
Congress intentionally delegated interpretive authority to the agency by enacting a statute with
“capacious terms” rather than “plain terms.” City of Arlington v. FCC, 569 U.S. 290, 296
(2013).

Despite becoming “the most-cited administrative law case of all time,” Jonathan R.
Siegel, The Constitutional Case for Chevron Deference, 71 VAND. L. REV. 937, 938 (2018),
“Chevron did not appear at first to be a major decision in administrative law,” Paul J. Larkin, Jr.,
Chevron and Federal Criminal Law, 32 J. L. & POL. 211, 215 n.25 (2017). “That a third of its
members were sidelined”—due to the recusals of Justices Marshall, Rehnquist, and O’Connor—

3Plaintiffs-Appellants also argue that the ATF waived reliance on Chevron deference. See Martin v. Soc.
Sec. Admin. Comm’r, 903 F.3d 1154, 1161 nn. 48-49 (11th Cir. 2018) (collecting cases from the circuit split as to
whether Chevron deference is waivable); see also Guedes v. ATF, 140 S. Ct. 789, 790 (2020) (Gorsuch, J.,
concurring in the denial of cert.) (explaining that the Supreme Court “has often declined to apply Chevron deference
when the government fails to invoke it”). And the ATF agrees, taking the position that, because its interpretation of
§ 5845(b) is the best interpretation, deference to its interpretation is “unnecessary,” so it “does not rely on Chevron
deference” in this case. Because we find, and hold, that Chevron deference does not apply in this case anyway
(because it does not apply to criminal statutes such as we have here), we need not consider or decide the issue of
waiver.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 10

“reduces the likelihood that the Court intended to make a tectonic shift in administrative law.”
Id. Regardless of its perceived intent—or lack thereof—Chevron did just that. Under its two-
step process:

First, applying the ordinary tools of statutory construction, the court must
determine whether Congress has directly spoken to the precise question at issue.
If the intent of Congress is clear, that is the end of the matter; for the court . . .
must give effect to the unambiguously expressed intent of Congress. But if the
statute is silent or ambiguous with respect to the specific issue, the question for
the court is whether the agency’s answer is based on a permissible construction of
the statute.

City of Arlington, 569 U.S. at 296 (quotation marks omitted) (relying on Chevron, 467 U.S. at
842-43). Restated a bit more succinctly: (1) is the statutory provision ambiguous and, if so, (2) is
the agency’s interpretation “permissible” within that ambiguity. If both steps are satisfied, the
court must defer to the agency’s interpretation regardless of the court’s own views of the correct
or better interpretation of the provision. See Chevron, 467 U.S. at 843-44. Later, in National
Cable & Telecommunications Association v. Brand X Internet Services, 545 U.S. 967, 982
(2005), the Court explained that Chevron deference means that an agency’s construction is
paramount to even a prior judicial construction, thus an agency may effectively overrule court
precedent.

B. Supreme Court Precedent

The Chevron Court was clear and unequivocal: “When a court reviews an agency’s
construction of the statute which it administers . . . [and] th[at] statute is silent or ambiguous with
respect to the specific issue[,] . . . [the] court may not substitute its own construction of [that]
statutory provision for a reasonable interpretation made by the . . . agency.” Chevron, 467 U.S.
at 842-44 (footnote omitted). Chevron did not draw any distinctions or identify any exceptions.

But in 2014, the Court said, “we have never held that the Government’s reading of a
criminal statute is entitled to any deference.” United States v. Apel, 571 U.S. 359, 369 (2014)
(emphasis added) (citing Crandon v. United States, 494 U.S. 152, 177 (1990) (Scalia, J.,
concurring in the judgment)). “Never” and “any” are absolutes, and the Court did not draw any
distinctions, add any qualifiers, or identify any exceptions. A few months later, in Abramski v.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 11

United States, 573 U.S. 169, 191 (2014), the Court quoted that same statement when rejecting a
petitioner’s argument that the ATF’s former construction of a criminal statute should inform the
Court’s decision. The Abramski Court explained:

The critical point is that criminal laws are for courts, not for the
Government, to construe. We think ATF’s old position no more relevant than its
current one—which is to say, not relevant at all. Whether the Government
interprets a criminal statute too broadly (as it sometimes does) or too narrowly (as
the ATF used to [regarding this provision]), a court has an obligation to correct its
error. Here, nothing suggests that Congress—the entity whose voice does
matter—limited [the provision’s] prohibition . . . in the way [the petitioner]
proposes.

Id. (citation omitted). Thus, the Court was clear, unequivocal, and absolute in saying that it has
“never held that the Government’s reading of a criminal statute is entitled to any deference.”
Apel, 571 U.S. at 369; Abramski, 573 U.S. at 191.

Unless the Court was mistaken in those two cases or exaggerating for effect, that bold,
absolute statement means that none of the Court’s prior cases applied Chevron deference (or any
deference) to an agency’s interpretation of a criminal statute. That merits some discussion.

Start with Chevron, which was not a criminal prosecution. The Environmental Protection
Agency (EPA) was the defendant; Chevron was just an intervenor. Chevron, 467 U.S. at 841
n.4. In implementing the Clean Air Act, which had created a permitting program for “stationary
sources” of air pollution and delegated that program to the States, the EPA promulgated
regulations “allow[ing] [the] State[s] to adopt a plantwide definition of the term ‘stationary
source,’” a term the Act had used, but not defined. Id. at 840 (footnote omitted). The NRDC
sued and “[t]he question presented . . . [was] whether EPA’s decision to allow States to treat all
of the pollution-emitting devices within the same industrial grouping as though they were
encased within a single ‘bubble’ [wa]s based on a reasonable construction of the statutory term
‘stationary source.’” Id. After creating the aforementioned “Chevron deference,” id. at 842-45,
the Court determined that the EPA’s definition was permissible within the Act’s ambiguity,
describing it as “an effective reconciliation of the[] twofold ends” of “reducing air pollution [and
protecting] economic growth,” id. at 866 (quotation marks, editorial marks, and citation omitted).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 12

To be sure, the Clean Air Act contains criminal penalties for—among other things such
as false reporting and tampering with monitoring devices—a permitted facility’s knowing
violation of its permit requirements, but the Chevron opinion contains no reference to the Act’s
criminal provisions nor did the case concern the possibility of any criminal sanction. No
reasonable reading of Chevron could stand for the proposition that the government’s
interpretation of a criminal statute is entitled to Chevron deference. Whether the Court intended
to (silently) exclude the criminal-provision issue or merely did not consider the criminal-
provision issue that was not before it, Chevron easily falls within the Court’s proclamations in
Apel and Abramski that it has never held that the government’s reading of a criminal statute is
entitled to deference.

The Court’s traditional approach, under the modern nondelegation doctrine, has been to
allow Congress to delegate to the executive branch the responsibility for defining crimes, but
only so long as it speaks “distinctly.” United States v. Grimaud, 220 U.S. 506, 519 (1911);
United States v. Eaton, 144 U.S. 677, 688 (1892). “This clear-statement rule reinforces
horizontal separation of powers . . . [and] compels Congress to legislate deliberately and
explicitly before departing from the Constitution’s traditional distribution of authority. Carter v.
Welles-Bowen Realty, Inc., 736 F.3d 722, 733 (6th Cir. 2013) (Sutton, J., concurring).
Obviously, Chevron—which applies only where there is statutory ambiguity—is the opposite of
a “clear statement.”

In Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687,
690 (1995), the Endangered Species Act made it a crime to “take” an endangered species and the
Department of the Interior’s (DOI’s) regulation said that such “taking” included the modification
or degradation of the species’ habitat. Sweet Home sought a declaratory judgment that the
statute did not support that regulation, making the regulation facially invalid. Id. at 692. The
Court did not employ a full Chevron analysis, though it cited Chevron “generally” in announcing
that it did “owe some degree of deference to the [DOI]’s reasonable interpretation,” due, in part,
to the “latitude the [Act] gives to the [DOI] in enforcing the statute.” Id. at 703-04; see also id.
at 708 (“When it enacted the ESA, Congress delegated broad administrative and interpretive
power to the [DOI].”). Thus, the Court appears to have been relying on the clear-statement
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 13

rule’s delegation of authority to the DOI as if the DOI were Congress itself. The Court also
included a footnote addressing the “rule of lenity,” in which it emphasized that it was not
reviewing a criminal prosecution but rather a facial challenge to an administrative regulation,
which did not necessarily invoke the “rule of lenity” just because “the governing statute
authorize[d] criminal enforcement.” Id. at 704 n.18 (distinguishing United States v. Thompson/
Center Arms Co., 504 U.S. 505, 517-18 & n.9 (1992)). While Babbitt certainly cited Chevron
and used the word deference with regard to the DOI’s interpretation, Babbitt did not discuss or
decide whether Chevron applied nor did it analyze the challenge using Chevron, just as it did not
decide whether the rule of lenity applied or analyze the challenge using the rule of lenity. “The
best that one can say . . . is that in Babbitt [] [the Court] deferred, with scarcely any explanation,
to an agency’s interpretation of a law that carried criminal penalties. . . . Babbitt’s drive-by
ruling, in short, deserves little weight.” Whitman v. United States, 574 U.S. 1003 (2014) (Scalia,
J., joined by Thomas, J., respecting the denial of cert.). While Babbitt certainly mentioned
deference, it did not hold that an agency’s interpretation of a criminal statute is entitled to
Chevron deference, and thus falls within the Court’s proclamations in Apel and Abramski that it
had never so held.

In United States v. O’Hagan, 521 U.S. 642, 669 (1997), the Securities Exchange Act had
criminalized “fraudulent trading,” which included the use of “material nonpublic information
concerning a pending tender offer,” and the Securities and Exchange Commission’s (SEC’s) rule
said that such trading was illegal even if the trader owed no duty to keep that information secret.
When the government convicted O’Hagan of this, he argued that the conviction was invalid
because the rule was invalid, because the SEC had exceeded its rulemaking authority. Id. at
666-67. The Court rejected that argument, finding that the statute expressly “delegates
definitional and prophylactic rulemaking authority to the [SEC],” id. at 667, and explained:
“Because Congress has authorized the [SEC] to prescribe legislative rules, we owe the [SEC]’s
judgment more than mere deference or weight.” Id. at 673 (quotation marks and citation
omitted). Although the Court quoted Chevron for the proposition that it “must accord the
[SEC]’s assessment controlling weight unless it is arbitrary, capricious, or manifestly contrary to
the statute,” id. (editorial and quotation marks omitted), it did not conduct a Chevron analysis or
present this as “Chevron deference.” The Court’s analysis relied on the statutory delegation of
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 14

authority to the SEC under the clear-statement rule. See id. at n.19; see also id. at 679 (Scalia, J.,
concurring in part) (drawing a distinction for situations “where (as here) no Chevron deference is
being given to the agency’s interpretation”). While O’Hagan used the word “deference,” it
cannot be read to support the proposition that the agency’s interpretation of a criminal statute
receives Chevron deference. O’Hagan falls within the Court’s proclamations in Apel and
Abramski that it had never so held.

We are not aware of any other Supreme Court opinion that would question the
proclamation in Apel and Abramski, but there are opinions that are consistent with it. In at least
three cases, the Court has indicated that the rule of lenity—the practical opposite of Chevron
deference—applies to ambiguous statutory provisions that have both civil and criminal
applications, thus resolving statutory ambiguities in favor of the criminal defendant rather than
the government. See, e.g., Leocal v. Ashcroft, 543 U.S. 1, 11 n.8 (2004); Thompson/Center Arms
Co., 504 U.S. at 517-18, 518 nn.9-10 (plurality); id. at 519 (Scalia, J., concurring in the
judgment); SWANCC v. U.S. Army Corps of Eng’rs, 531 U.S. 159, 173-74, 174 n.8 (2001).

Considered altogether, if we take the Court at its word, it has never held that a court must
necessarily grant Chevron deference to the government’s interpretation of an ambiguous
criminal statute. More to the point for present purposes, we are aware of no Supreme Court
opinion that compels us to apply Chevron deference to the ATF’s interpretation of § 5854(b)
here.

C. Circuit Court Precedent

Our review of Sixth Circuit precedent reveals that we generally do not apply Chevron
deference to an administering agency’s interpretation of a criminal statute, as we have explained:

The special deference required by Chevron is based on the expertise of an
administrative agency in a complex field of regulation with nuances perhaps
unfamiliar to the federal courts. Unlike environmental regulation or occupational
safety, criminal law and the interpretation of criminal statutes is the bread and
butter of the work of federal courts.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 15

Dolfi v. Pontesso, 156 F.3d 696, 700 (6th Cir. 1998). But, considered as a whole, Sixth Circuit
precedent appears to provide us with no controlling authority as to whether we must or must not
apply Chevron deference to the definition of machine gun in § 5845(b).

To be sure, in Esquivel-Quintana v. Lynch, 810 F.3d 1019, 1023-24 (6th Cir. 2016), we
relied on Babbitt, 515 U.S. at 704 n.18, to apply Chevron deference to the Board of Immigration
Appeals’ interpretation of an immigration statute with both criminal and civil penalties. But the
Supreme Court reversed that decision based on an alternative analysis and, in so doing, expressly
refused to decide the applicability of Chevron deference. Esquivel-Quintana v. Sessions,
137 S. Ct. 1562, 1572-73 (2017). Thus, our opinion in Esquivel is at most persuasive authority.
See CIC Servs., LLC v. IRS, 925 F.3d 247, 257 (6th Cir. 2019), cert. granted 140 S. Ct. 2737
(2020) (declining to follow earlier Sixth Circuit precedent that had been reversed on other
grounds).

Our reasoning in Esquivel was that “[t]he Supreme Court has said that we must follow
Chevron in cases involving the Board’s interpretations of immigration laws.” Esquivel, 810 F.3d
at 1024 (citations omitted). But the Supreme Court has not issued similarly on-point opinions
involving the definition of “machinegun” in § 5845(b). The most analogous precedent is
Thompson/Center Arms Company, 504 U.S. at 517-18 (plurality opinion), in which the Court
applied the rule of lenity (not Chevron deference) to statutory definitions in the National
Firearms Act, 26 U.S.C. § 5845. See also id. at 519 (Scalia, J., concurring in the judgment).

And we have never held that Chevron deference applies to an agency’s interpretation of a
purely criminal statute, such as the ban on possessing a machine gun in 18 U.S.C. § 922(o). See
Esquivel, 810 F.3d at 1027 (Sutton, J., concurring in part and dissenting in part) (“But all can
agree that . . . Chevron has no role to play in the interpretation of criminal statutes.”); United
States v. One TRW, Model M14, 7.62 Caliber Rifle, 441 F.3d 416, 420 & n.3 (6th Cir. 2006)
(considering an ATF ruling interpreting § 5845(b), finding the deference question unsettled, and
leaving it undecided, but noting that “[t]his matter is further complicated by the fact that [] we
are interpreting a criminal statute, and under the rule of lenity ambiguities are generally resolved
in favor of the party accused of violating the law, even in a civil proceeding”). Instead, we have
found that a court’s deferring to an agency’s interpretation of a criminal statute would be
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 16

problematic, if not prohibited. See United States v. Dodson, 519 F. App’x 344, 349 (6th Cir.
2013) (“The ATF does not have the ability to redefine or create exceptions to Congressional
statutes.”); Boettger v. Bowen, 923 F.2d 1183, 1186 (6th Cir. 1991) (“There is no intermediary to
provide further clarification between Congress and the persons who are subject to penalty.”); see
also, e.g., United States v. Havis, 907 F.3d 439, 451 (6th Cir. 2018) (Thapar, J., concurring),
rev’d en banc, 927 F.3d 382 (6th Cir. 2019) (“How is it fair in a court of justice for judges to
defer to one of the litigants? . . . Such deference is found nowhere in the Constitution—the
document to which judges take an oath.”); Carter, 736 F.3d at 732 (Sutton, J., concurring)
(“Chevron describes how judges and administrators divide power. But power to define crimes is
not theirs to divide.”).

Since Apel and Abramski, other federal courts have split as to whether those opinions
mandate that a court may not, or merely permit that it need not, defer to an agency’s
interpretation of a criminal statute. Compare United States v. Kuzma, 967 F.3d 959, 971 (9th
Cir. 2020), cert. denied, 2020 WL 7132664 (2020) (“Because criminal laws are for courts, not
for the Government, to construe, the Supreme Court has repeatedly rejected the view that the
Government’s reading of a criminal statute is entitled to any deference.” (quotation marks and
citations omitted)), United States v. Balde, 943 F.3d 73, 83 (2d Cir. 2019) (“[T]he Supreme
Court has clarified that law enforcement agency interpretations of criminal statutes are not
entitled to deference[.]”), United States v. Garcia, 707 F. App’x 231, 234 (5th Cir. 2017)
(“The Supreme Court has now resolved this uncertainty, instructing that no deference is owed to
agency interpretations of criminal statutes.”), and Gutierrez-Brizuela v. Lynch, 834 F.3d 1142,
1155 (10th Cir. 2016) (Gorsuch, J., concurring) (“The Supreme Court has expressly instructed us
not to apply Chevron deference when an agency seeks to interpret a criminal statute.”), with
Aposhian v. Barr, 958 F.3d 969, 982 (10th Cir. 2020), and Guedes v. Bureau of Alcohol,
Tobacco, Firearms & Explosives, 920 F.3d 1, 25 (D.C. Cir. 2019), cert. denied, 140 S. Ct. 789
(2020) (acknowledging that “the Supreme Court has signaled some wariness about deferring to
the government’s interpretations of criminal statutes,” but distinguishing Apel and Abramski and
holding that Babbitt still “govern[s] us here”).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 17

We are not the first circuit court to review the ATF’s Final Rule on bump stocks. The
Tenth and D.C. Circuits have each concluded that an administering agency’s interpretation of a
criminal statute is entitled to Chevron deference, and, under that deferential standard of review,
found the ATF’s Final Rule a permissible interpretation of § 5845(b). Both of those courts found
themselves bound by circuit precedent that an agency’s interpretation of a criminal statute is
entitled to Chevron deference. See Aposhian, 958 F.3d at 982 (rejecting “a general rule against
applying Chevron to agency interpretations of statutes with criminal law implications” because
“controlling [Tenth Circuit] precedent points in the other direction”). The D.C. Circuit found
that, in the securities context, it had frequently granted Chevron deference to the SEC
notwithstanding the fact that violation of securities laws “often triggers criminal liability.”
Guedes, 920 F.3d at 24 (citations omitted). However, as discussed above, we have no
comparable precedent and, in fact, our precedent suggests the opposite. 4 And, as mentioned,
there is already a split among the Circuits on the meaning of Apel and Abramski and whether the
Supreme Court now requires courts not to give any deference to agency interpretations of
criminal statutes. With this decision we are joining one side of a circuit split, not creating a
circuit split.

D. Whether an Agency’s Interpretation of a
Criminal Statute is Entitled to Chevron Deference

Having found that Supreme Court and Sixth Circuit precedent neither require nor
foreclose a specific holding, we turn to the merits of the question. Chevron deference is typically
justified on two rationales: (1) an administering agency is more likely than a generalist court to
determine the best interpretation of a statute because of the agency’s specialized “expertise” in
the statute’s subject matter; and (2) by employing ambiguous terms rather than clear, specific
language when drafting a statute, Congress ostensibly was deliberately delegating its lawmaking
responsibilities to the agency. Arangure v. Whitaker, 911 F.3d 333, 341-42 (6th Cir. 2018).
Whatever the merits of either rationale with respect to civil statutes, see Michigan v. EPA,
576 U.S. 743, 760-64 (2015) (Thomas, J., concurring) (questioning the justifications of Chevron

4We do not hear securities cases as frequently as the D.C. and Second Circuits, and we have never reached
the issue of Chevron deference to the SEC’s interpretation of a criminal statute. See, e.g., SEC v. Mohn, 465 F.3d
647, 650 n.2 (6th Cir. 2006) (noting that the SEC conceded that “de novo review is appropriate” in that case).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 18

deference and whether such deference is constitutional), neither holds water with respect to
criminal statutes. Furthermore, deference to the administering agency’s interpretation of a
criminal statute directly conflicts with the rule of lenity and raises serious constitutional
concerns. Consequently, we must hold that no deference is owed to an agency’s interpretation of
a criminal statute.

1. Criminal Laws Reflect the Moral Judgments and “Expertise” of the Community

“[P]ractical agency expertise is one of the principal justifications behind Chevron
deference.” Pension Benefit Guar. Corp. v. LTV Corp., 496 U.S. 633, 651-52 (1990) (citing
Chevron, 467 U.S. at 865). The Supreme Court’s position has been that “agencies are more
likely to get the answer right, given their expertise.” Arangure, 911 F.3d at 341. For example,
the Court justified giving Chevron deference to the Social Security Administration’s
interpretation of the Social Security Act because of “the related expertise of the Agency,” “the
complexity of [the] administration” of the statute, and “the careful consideration the Agency
[gave] the question over a long period of time.” Barnhart v. Walton, 535 U.S. 212, 222 (2002).

Notwithstanding the ATF’s frequent reversals on major policy issues, we understand that
the Court would consider the bureaucrats at the ATF as experts in firearms technology. But that
technical knowledge is inapposite to the question of what should be criminally punished and
what should not. Criminal statutes reflect the value-laden, moral judgments of the community as
evidenced by their elected representatives’ policy decisions. See Gregg v. Georgia, 428 U.S.
153, 175 (1976) (“In a democratic society, legislatures, not courts, are constituted to respond to
the will and consequently the moral values of the people.” (cleaned up)); Mullaney v. Wilbur,
421 U.S. 684, 700 (1975) (noting “the moral force of the criminal law”); United States v. Bass,
404 U.S. 336, 348 (1971) (“[C]riminal punishment [] represents the moral condemnation of the
community.”); OLIVER WENDELL HOLMES, JR., THE COMMON LAW 50 (1881) (“[C]riminal
liability . . . is founded on blameworthiness.”). Since our country’s founding, it has been
understood that the public is both capable of and necessary to the determination of right from
wrong legally and morally. See, e.g., THE FEDERALIST NO. 83, at 433 (Alexander Hamilton)
(G.W. Carey and J. McClellan eds., 2001) (explaining why many consider juries in criminal
cases to be “essential in a representative republic,” a “friendly aspect to liberty,” and a necessary
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 19

safeguard against “[a]rbitrary impeachments, arbitrary methods of prosecuting pretended
offences, [and] arbitrary punishments upon arbitrary convictions”); John Adams, Diary Entry
Feb. 12, 1771, in THE WORKS OF JOHN ADAMS, VOL. II, at 254 (C.F. Adams, ed., 1850)
(“The general rules of law and common regulations of society . . . are well enough known to
ordinary jurors. The great principles of the constitution are intimately known; they are sensibly
felt by every Briton; it is scarcely extravagant to say they are drawn in and imbibed with the
nurse’s milk and first air.”).

Indeed, our criminal laws continue to reflect the public’s moral judgments. See Kahler v.
Kansas, 140 S. Ct. 1021, 1048 (2020) (Breyer, J., dissenting) (discussing the “deeply entrenched
and widely recognized moral principles underpinning our criminal laws”); Gregg, 428 U.S. at
183 (“[C]apital punishment is an expression of society’s moral outrage at particularly offensive
conduct.”). Our criminal laws, for example, incorporate gradations of punishment to account for
the moral culpability of the defendant and the severity of the crime committed. And legislators
have long recognized that we as a community condemn and punish a premeditated murder more
harshly than one committed in the heat of passion, which in turn is punished more severely than
one unintentionally committed due to negligence. See Mullaney, 421 U.S. at 697-98 (explaining
that “the criminal law of Maine, like that of other jurisdictions, is concerned not only with guilt
or innocence in the abstract but also with the degree of criminal culpability”).

The training for such policy determinations does not come from a graduate school
education or decades of bureaucratic experience. Rather, one develops the expertise necessary to
make moral judgments from sources of a more humble and local origin: one’s family and
upbringing. This learning is further informed by relationships with friends and neighbors, the
practice of one’s faith, and participation in civic life. That this education is accessible to
everyone and anyone further enhances, not diminishes, the legitimacy of these community-based
judgments. That is why, from the founding, the Supreme Court has held that there can be no
federal common-law crimes and that only the people’s representatives in Congress may enact
federal criminal laws. See United States v. Davis, 139 S. Ct. 2319, 2325 (2019) (quoting United
States v. Hudson, 7 Cranch 32, 34 (1812)). And what the Supreme Court has previously said
about a federal court’s ability to create a crime is equally relevant to a federal agency’s ability to
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 20

do so: “[B]ecause criminal punishment usually represents the moral condemnation of the
community, legislatures and not [agencies] should define criminal activity.” Bass, 404 U.S. at
348.

Moreover, mastery of one field does not mean mastery of all. The ATF is not an expert
on community morality, so the rationale of deferring to “agency expertise” on this question fails.
And there is great risk if the responsibility of making moral condemnations is assigned to
bureaucrats in the nation’s capital who are physically, and often culturally, distant from the rest
of the country. Federal criminal laws are not administrative edicts handed down upon the masses
as if the administrators were God delivering the Ten Commandments to Moses on Mount Sinai.

Whether ownership of a bump-stock device should be criminally punished is a question
for our society. Indeed, the Las Vegas shooting sparked an intense national debate on the
benefits and risks of bump-stock ownership. And because criminal laws are rooted in the
community, the people determine for themselves—through their legislators—what is right or
wrong. The executive enforces those determinations. It is not the role of the executive—
particularly the unelected administrative state—to dictate to the public what is right and what is
wrong.

The stakes of any determination are significant. Under the ATF’s Final Rule, every
bump-stock owner will potentially face not only a loss of liberty in the form of incarceration, but
also the stigma and hardships that accompany a felony conviction. See McMillan v.
Pennsylvania, 477 U.S. 79, 103 (1986) (Stevens, J., dissenting) (explaining that a “high standard
of proof is required because of the immense importance of the individual interest in avoiding
both the loss of liberty and the stigma that results from a criminal conviction”). But whether
bump-stock owners—heretofore law-abiding citizens—should now potentially be subject to
substantial fines, imprisonment, and damning social stigmas is a question to whose answer an
expertise in firearms technology contributes nothing. So, the ATF’s firearms expertise is not
germane to the question of whether bump-stock ownership should be condemned and punished.

Finally, to the extent that the ATF is not determining what the agency thinks should be
punished but is instead merely interpreting what Congress has already decided should be
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 21

punished, that determination also wrongfully relies on an expertise that the ATF lacks. Rather,
as we have already explained, interpreting criminal statutes falls within the expertise of the
courts. Dolfi, 156 F.3d at 700; see also Alexander v. Gardner-Denver Co., 415 U.S. 36, 57
(1974) (“[T]he resolution of statutory or constitutional issues is a primary responsibility of
courts.”); Zipf v. Am. Tel. and Tel. Co., 799 F.2d 889, 893 (3d Cir. 1986) (“[S]tatutory
interpretation is not only the obligation of the courts, it is a matter within their peculiar
expertise.”). Indeed, “we judges are experts on one thing—interpreting the law.” Wilson v.
Safelite Grp., Inc., 930 F.3d 429, 442 (6th Cir. 2019) (Thapar, J., concurring) (internal alteration
omitted) (quoting Utah v. Rasabout, 356 P.3d 1258, 1285 (Utah 2015) (Lee, A.C.J., concurring
in part and concurring in the judgment) (emphasis omitted)). So, the rationale of deferring to
agency expertise does not apply here either.

In sum, for criminal statutes, where the primary question is what conduct should be
condemned and punished, the first rationale of Chevron deference—deferring to an agency’s
expertise—is unconvincing because the agency’s technical specialized knowledge does not assist
in making the value-laden judgment underlying our criminal laws. That judgment is reserved to
the people through their duly elected representatives in Congress.

2. Deference in the Criminal Context Violates the Separation of Powers

“The Chevron Court justified deference on the premise that a statutory ambiguity
represents an ‘implicit’ delegation to an agency to interpret a ‘statute which it administers.’”
Epic Sys. Corp. v. Lewis, 138 S. Ct. 1612, 1629 (2018) (quoting Chevron, 467 U.S. at 842, 844).
According to the Supreme Court, “Chevron thus provides a stable background rule against which
Congress can legislate: Statutory ambiguities will be resolved, within the bounds of reasonable
interpretation, not by the courts but by the administering agency.” City of Arlington, 569 U.S. at
296. Courts ostensibly know that Congress is deliberately intending to delegate some of its
legislative responsibilities because “Congress knows to speak in plain terms when it wishes to
circumscribe, and in capacious terms when it wishes to enlarge, agency discretion.” Id.

Notwithstanding Article I’s mandate that “[a]ll legislative Powers herein granted shall be
vested in a Congress of the United States,” U.S. CONST. art. 1, § 1., the Supreme Court has
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 22

permitted Congress to delegate some of its lawmaking responsibilities to executive-branch
agencies so long as Congress provides an “intelligible principle” to which the administering
agency is directed to conform. Mistretta v. United States, 488 U.S. 361, 372 (1989) (quoting
J.W. Hampton, Jr., & Co. v. United States, 276 U.S. 394, 409 (1928)); see also supra Part III.B
(discussing the “clear statement” rule). The Court is of the opinion that “in our increasingly
complex society, replete with ever changing and more technical problems, Congress simply
cannot do its job absent an ability to delegate power under broad general directives.” Id.
Generally, the Supreme Court has made this “clear statement” or “intelligible principle” standard
a relatively low bar that Congress may overcome with fairly indefinite instructions. See, e.g.,
Yakus v. United States, 321 U.S. 414, 420, 427 (1944) (upholding the Emergency Price Control
Act of 1942, which instructed the Price Administrator to fix prices of commodities that are “in
his judgment [] generally fair and equitable”); Nat’l Broad. Co. v. United States, 319 U.S. 190,
225-26 (1943) (upholding the Communications Act of 1934, which permitted the Federal
Communications Commission to grant broadcast licenses “if public convenience, interest, or
necessity will be served thereby”); N.Y. Cent. Sec. Corp. v. United States, 287 U.S. 12, 24-25
(1932) (upholding the Transportation Act of 1920, which empowered the Interstate Commerce
Commission to authorize the acquisition of one railroad by another if it is in the “public
interest”). At the same time, the Supreme Court has made clear that “Congress is not permitted
to abdicate or to transfer to others the essential legislative functions with which it is thus
vested . . . if our constitutional system is to be maintained.” A.L.A. Schechter Poultry Corp. v.
United States, 295 U.S. 495, 529-30 (1935) (quoting Pan. Ref. Co. v. Ryan, 293 U.S. 388, 421
(1935)).

Therefore, a court’s deferring to an executive-branch agency’s interpretation of a
congressional statute naturally raises separation-of-powers concerns. See, e.g., Arangure,
911 F.3d at 338 (explaining that “[w]hen courts find ambiguity where none exists, they are
abdicating their judicial duty,” “impermissibly expand[ing] an already-questionable Chevron
doctrine,” and “abrogat[ing the] separation of powers”) (citations omitted); Havis, 907 F.3d at
452 (Thapar, J., concurring) (“[D]eference [that] would allow the same agency to make the rules
and interpret the rules . . . is contrary to any notion the founders had of separation of powers.”);
Lynch, 810 F.3d at 1023-24 (“Left unchecked, deference to agency interpretations of laws with
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 23

criminal applications threatens a complete undermining of the Constitution’s separation of
powers.”). These separation-of-powers concerns have even greater force in the criminal context.
See, e.g., Davis, 139 S. Ct. at 2325.

The “separate and distinct exercise of the different powers of government” is “essential to
the preservation of liberty.” THE FEDERALIST NO. 51, at 268 (James Madison or Alexander
Hamilton). The separation of powers serves as “the great security against a gradual
concentration of the several powers in the same department.” Id. In addition to “protect[ing]
each branch of government from incursion by the others,” most importantly, “[t]he structural
principles secured by the separation of powers protect the individual as well.” Bond v. United
States, 564 U.S. 211, 222 (2011).

Each branch’s role and responsibility with regard to criminal statutes is clear. First,
“[o]nly the people’s elected representatives in the legislature are authorized to ‘make an act a
crime.’” Davis, 139 S. Ct. at 2325 (quoting Hudson, 7 Cranch at 34). Next, the executive is
responsible for enforcing criminal statutes, and it retains “exclusive authority and absolute
discretion to decide whether to prosecute a case.” United States v. Nixon, 418 U.S. 683, 693
(1974) (citing Confiscation Cases, 74 U.S. 454 (1868)). Finally, it is for the courts to “say what
the law is,” including the criminal law. Marbury v. Madison, 1 Cranch 137, 177 (1803).

Even under a well-balanced system, the power of the federal government, particularly the
executive branch, is formidable. No matter how well-prepared a defendant may be, his defense
will pale in comparison to the resources, institutional knowledge, and personnel available to the
federal government. If we defer to the federal prosecutor’s interpretation of a criminal statute,
this imbalance becomes even more lopsided. Whatever separation-of-powers issues are created
by the delegation of civil lawmaking, the problems are much more profound when the matter
involves criminal legislation. Specifically, deferring to the executive branch’s interpretation of a
criminal statute presents at least three serious separation-of-powers concerns: (1) it puts
individual liberty at risk by giving one branch the power to both write the criminal law and
enforce the criminal law; (2) it eliminates the judiciary’s core responsibility of determining a
criminal statute’s meaning; and (3) it reduces, if not eliminates, the public’s ability to voice its
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 24

moral judgments because it transfers the decision-making from elected representatives in the
legislature to unaccountable bureaucrats in the executive’s administrative agencies.

First, giving one branch the power to both draft and enforce criminal statutes jeopardizes
the people’s right to liberty. The concern over the potential abuse of power if the executive can
define crimes predates our nation’s founding. See THE FEDERALIST NO. 47, at 251 (James
Madison) (quoting Baron de Montesquieu that “[t]here can be no liberty where the legislative
and executive powers are united in the same person, or body of magistrates”); 1 WILLIAM
BLACKSTONE, COMMENTARIES *146 (1753) (“In all tyrannical governments, the supreme
magistracy, or the right of both making and of enforcing the laws, is vested in one and the same
man, or one and the same body of men; and wherever these two powers are united together, there
can be no public liberty.”); JOHN LOCKE, SECOND TREATISE OF CIVIL GOVERNMENT § 143, pp.
324-25 (T. Hollis ed., 1764) (1690) (“[I]t may be too great a temptation to human frailty, apt to
grasp at power, for the same persons, who have the power of making laws, to have also in their
hands the power to execute them, whereby they may exempt themselves from obedience to the
laws they make, and suit the law, both in its making, and execution, to their own private
advantage, and thereby come to have a distinct interest from the rest of the community, contrary
to the end of society and government.”); Case of Proclamations, 12 Co. Rep. 74, 75 (K.B. 1611)
(“[T]he King cannot change any part of the common law, nor create any offence by his
proclamation, which was not an offence before, without Parliament.”).

The executive branch plays an important role in upholding the rule of law and making
society safer. But the immense power necessary to achieve those virtuous ends necessarily
means that that power is at risk of being abused. If the executive branch wants to prosecute
someone for something that is not yet a crime, it could use Chevron deference to interpret a
statute so as to criminalize the activity and then prosecute an individual for doing it. See
Whitman v. United States, 135 S. Ct. 352, 353 (2014) (Scalia, J., concurring in denial of cert.)
(“With deference to agency interpretations of statutory provisions to which criminal prohibitions
are attached, federal administrators can in effect create (and uncreate) new crimes at will, so long
as they do not roam beyond ambiguities that the laws contain.”).
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Second, it is for the judiciary to “say what the law is,” Marbury, 1 Cranch at 177, and this
remains equally, if not especially, true for criminal laws. See Abramski, 573 U.S. at 191
(“[C]riminal laws are for courts, not for the Government, to construe.”). It is well-established
that “the resolution of statutory or constitutional issues is a primary responsibility of courts.”
Alexander, 415 U.S. at 57. Notwithstanding this principle, the question of Chevron deference
considers whether the judiciary or the executive should have the final say on an indeterminate
statute’s meaning. The implications of each possibility are clear. Granting the executive the
right both to determine a criminal statute’s meaning and to enforce that same criminal statute
poses a severe risk to individual liberty. Entrusting the interpretation of criminal laws to the
judiciary, and not the executive, mitigates that risk and protects against any potential abuses of
government power. See BLACKSTONE at *268 (“[T]he public liberty . . . cannot subsist long in
any state unless the administration of common justice be in some degree separated both from the
legislative and also from the executive power.”).

Third, because it is the public’s responsibility to determine what conduct should be
condemned, see supra Part III.D.1, “[o]nly the people’s elected representatives in Congress have
the power to write new federal criminal laws.” Davis, 139 S. Ct. at 2323. Indeed, “Congress
alone has the institutional competence, democratic legitimacy, and (most importantly)
constitutional authority to revise statutes in light of new social problems and preferences.” Wis.
Cent. Ltd. v. United States, 138 S. Ct. 2067, 2074 (2018). However, Chevron deference, in this
context, empowers the agency rather than Congress to define the scope of what should be
criminalized. Cf. Abramski, 573 U.S. at 191 (emphasizing that “Congress,” not the ATF, is “the
entity whose voice does matter”). If Congress were “to hand responsibility for defining crimes
to relatively unaccountable [public officials],” it would “erod[e] the people’s ability to oversee
the creation of the laws they are expected to abide” and would “leave people with no sure way to
know what consequences will attach to their conduct.” Davis, 139 S. Ct. at 2323, 2325.

Of all the separation-of-powers concerns identified, perhaps this is the most troubling:
the bureaucrats at the agency are unaccountable to the public. If the agency adopts an
interpretation contrary to the will of the people, what recourse does the public have? Unlike
legislators, agency bureaucrats are not subject to elections and are often further protected from
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 26

removal by civil-service restrictions. Even when an agency implements the will of the public
correctly, that determination may still violate the separation of powers. Because the community
has the right to determine what moral wrongs should be punished—a practice that predates our
Constitution—that responsibility may be entrusted to only the branch most accountable to the
people: the legislature. And it may not be blithely delegated away. See LOCKE, § 141, at 322
(“The legislative cannot transfer the power of making laws to any other hands: for it being but a
delegated power from the people, they who have it cannot pass it over to others.”).

Because such deference in the criminal context would violate the Constitution’s
separation of powers and poses a severe risk to individual liberty, we must hold that an
administering agency’s interpretation of a criminal statute is not entitled to Chevron deference.

3. Fair Notice and the Rule of Lenity

We have established that the two principal justifications for Chevron deference in the
civil context—deferring to an agency’s subject-matter expertise and respecting Congress’s
delegation of its lawmaking powers—are unpersuasive in the criminal context. Nor does a third
justification for Chevron deference fit into this criminal context: the “background presumption”
of statutory interpretation that Congress means for federal agencies to resolve the ambiguities
that it leaves in its statutes. City of Arlington, 569 U.S. at 296. Some have suggested that this
interpretive presumption makes sense in light of the judiciary’s traditional mandamus practices.
See, e.g., United States v. Mead Corp., 533 U.S. 218, 241-43 (2001) (Scalia, J., dissenting).
Whether or not true in the civil context, cf. Aditya Bamzai, The Origins of Judicial Deference to
Executive Interpretation, 126 YALE L.J. 908 (2017), the judiciary’s historical interpretive
principles in no way support Chevron’s background presumption in the criminal context. To the
contrary, ambiguities in criminal statutes have always been interpreted against the government,
not in favor of it. As Chief Justice Marshall noted, “[t]he rule that penal laws are to be construed
strictly, is perhaps not much less old than construction itself.” United States v. Wiltberger,
18 U.S. 76, 95 (1820). So we would be remiss if we did not acknowledge that Chevron
deference to an agency’s interpretation of criminal statutes conflicts with the rule of lenity and
raises serious concerns.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 27

The rule of lenity instructs courts that “ambiguity concerning the ambit of criminal
statutes should be resolved in favor of lenity.” Rewis v. United States, 401 U.S. 808, 812 (1971)
(citation omitted). Unlike descriptive canons of statutory interpretation that help to resolve
indeterminacies about a statute’s intended meaning, the rule of lenity is a “purely normative”
canon rooted in fair-notice concerns. CALEB NELSON, STATUTORY INTERPRETATION 110 (2011);
see also McBoyle v. United States, 283 U.S. 25, 27 (1931) (“Although it is not likely that a
criminal will carefully consider the text of the law before he murders or steals, it is reasonable
that a fair warning should be given to the world in language that the common world will
understand, of what the law intends to do if a certain line is passed.”). “The rule ‘applies only
when, after consulting traditional canons of statutory construction, we are left with an ambiguous
statute.’” Shular v. United States, 140 S. Ct. 779, 787 (2020) (quoting United States v. Shabani,
513 U.S. 10, 17 (1994)).

We have long accepted that deference in the criminal context conflicts with the rule of
lenity and raises serious fair-notice concerns. See, e.g., Lynch, 810 F.3d at 1023-24 (explaining
that “[t]he rule of lenity ensures that the public has adequate notice of what conduct is
criminalized, and preserves the separation of powers by ensuring that legislatures, not executive
officers, define crimes” and that if “[l]eft unchecked, deference to agency interpretations of laws
with criminal applications threatens a complete undermining of the Constitution’s separation of
powers”); Carter, 736 F.3d at 729-736 (Sutton, J., concurring) (discussing how and why
Chevron deference to agency interpretations of criminal statutes “offends the rule of lenity”);
Dodson, 519 F. App’x at 349 n.4 (“Statutes that require agency action to clarify their terms may
raise fair notice and vagueness concerns.”); One TRW, Model M14, 7.62 Caliber Rifle, 441 F.3d
at 420 n.3 (noting that giving Chevron deference to the ATF’s interpretation is “further
complicated by the fact that [] we are interpreting a criminal statute, and under the rule of lenity
ambiguities are generally resolved in favor of the party accused of violating the law”).

Returning to our prior consideration of Babbitt, 515 U.S. at 704 n.18 (“We have never
suggested that the rule of lenity should provide the standard for reviewing facial challenges to
administrative regulations whenever the governing statute authorizes criminal enforcement.”),
we must recognize that the Supreme Court has never expressly reaffirmed that footnote and has
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 28

indeed undercut it in subsequent cases. See, e.g., Leocal, 543 U.S. at 11 n.8 (“Because we must
interpret the statute consistently, whether we encounter its application in a criminal or
noncriminal context, the rule of lenity applies.”). Moreover, the scope of the Babbitt footnote
certainly appears limited. The Court admitted that there might “exist regulations whose
interpretations of statutory criminal penalties provide such inadequate notice of potential liability
as to offend the rule of lenity,” but that the regulation before it (in Babbitt) “cannot be one of
them” because that regulation had “existed for two decades,” which was enough time to “give[] a
fair warning of its consequences.” Babbitt, 515 U.S. at 704 n.18. What if the agency’s
regulation is not nearly so longstanding? Or, as in this case, what if the agency is reversing a
longstanding policy? See Guedes v. ATF, 140 S. Ct. 789, 790 (2020) (Gorsuch, J., concurring in
denial of cert.) (“How, in all this, can ordinary citizens be expected to keep up—required not
only to conform their conduct to the fairest reading of the law they might expect from a neutral
judge, but forced to guess whether the statute will be declared ambiguous; to guess again
whether the agency’s initial interpretation of the law will be declared ‘reasonable’; and to
guess again whether a later and opposing agency interpretation will also be held ‘reasonable’?”).
Here, the ATF had a regulation, unaltered for nearly two decades: nonmechanical bump stocks
were not machine guns. See Final Rule, 83 Fed. Reg. at 66,531. The Babbitt footnote did not
specify how longstanding a regulation must be in order to satisfy fair-notice concerns or whether
this standard changes when an agency reverses a previous position. Thus, we face the scenario
opposite to that addressed in the Babbitt footnote. In the end, we need not decide those questions
today because we find on other grounds, for the reasons discussed supra, that the ATF’s
interpretation of § 5845(b) is not entitled to Chevron deference.

E. Summary

Whatever the merits of giving Chevron deference to an agency’s interpretation of civil
statutes, the principal rationales behind that policy cannot be extended to support giving
deference to an agency’s interpretation of criminal statutes. Declining to grant Chevron
deference to agency interpretations of criminal statutes respects the community’s responsibility
to make value-laden judgments on what should be criminalized, upholds the separation of
powers, complies with the rule of lenity, and avoids fair-notice concerns. Because the ATF’s
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 29

interpretation of § 5845(b) is not entitled to Chevron deference, we must determine the best
meaning of the criminal statute and whether a bump stock falls within the statutory definition of
a machine gun.

IV. Analysis: Statutory Interpretation

It is a “‘fundamental canon of statutory construction’ that words generally should be
‘interpreted as taking their ordinary, contemporary, common meaning . . . at the time Congress
enacted the statute.’” Wis. Cent. Ltd., 138 S. Ct. at 2074 (quoting Perrin v. United States,
444 U.S. 37, 42 (1979)). The separation of powers requires that we interpret the statute “as
written,” and “we may not rewrite the statute simply to accommodate [a] policy concern.”
Henry Schein, Inc. v. Archer & White Sales, Inc., 139 S. Ct. 524, 529, 531 (2019).

Whether a bump stock falls within § 5845(b)’s definition of a machine gun is a question
of statutory interpretation, and “[t]he starting point for any question of statutory interpretation is
the language of the statute itself.” United States v. Coss, 677 F.3d 278, 283 (6th Cir. 2012)
(internal quotation marks and citation omitted). In determining the meaning of a statute, we have
several interpretative tools at our disposal, including contemporaneous dictionaries, the structure
and context of the rest of the statute, and descriptive canons of statutory interpretation, such as
ejusdem generis, expressio unius, and noscitur a sociis. See Keen v. Helson, 930 F.3d 799,
802-04 (6th Cir. 2019); Arangure, 911 F.3d at 339-40. For the following reasons, we find that a
bump stock does not fall within the statutory definition of a machine gun.

A. “Single Function of the Trigger”

The parties dispute the meaning of the phrase “single function of the trigger,” as used in
§ 5845(b). Plaintiffs-Appellants argue that the phrase “refers to the mechanical process through
which the trigger goes (what the firearm is doing)” as opposed to “what the shooter is doing.”
The ATF argues (at least at the moment) that it means “a single pull of the trigger and analogous
motions.” Final Rule, 83 F.R. at 66,553. The ATF claims that “function” does not refer to “the
precise mechanical operation of a specific type of trigger,” but rather “the action that enables the
weapon to shoot,” i.e., “the shooter’s initial pull of the trigger.”
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 30

Put differently, the question is whether “function” is referring to the mechanical process
(i.e., the act of the trigger’s being depressed, released, and reset) or the human process (i.e., the
shooter’s pulling, or otherwise acting upon, the trigger).5 Under the former, a bump stock does
not fundamentally change the mechanical process: in order for a single shot to be fired, the
trigger must be depressed, released, and reset before another shot may be fired. Under this
interpretation, the bump-stock-attached semiautomatic firearm clearly is not a machine gun as it
is not capable of firing more than one shot for each depressed-released-reset cycle the trigger
completes.

Under the latter interpretation, the bump stock requires that the shooter pull—as in
physically bend his or her finger and apply force to pull the trigger—once. After the shooter
pulls the trigger once, the bump stock enables the continuous firing cycle to begin and continue
without requiring the shooter to physically move his or her finger and pull the trigger again;
indeed, a bump stock is successfully operated when the shooter keeps his or her trigger finger
stationary. Under this interpretation, the bump-stock-attached semiautomatic firearm would be a
machine gun because the firearm shoots multiple shots despite the shooter’s pulling the trigger
only once.

We have not previously addressed the meaning of the phrase “single function of the
trigger” as used in § 5845(b).6 The district court concluded that both interpretations were
reasonable and, because it was operating under a Chevron-deference framework, upheld the

5We agree with both parties that a firearm’s trigger does not necessarily need to be “pulled” in order to
constitute a trigger or for the firearm to constitute a machine gun. As the Final Rule aptly explains, automatic
firearms can have multiple types of triggers, such as a button that is pushed or an electric switch that is flipped.
Bump-Stock-Type Devices, 83 Fed. Reg. 66,534, 66,518 n.5 (Dec. 26, 2018). We employ the term “pull” because
that is the most common action used to act upon a trigger. Indeed, the parties’ dispute does not center on whether
“function” includes the operation of a trigger that is pulled or a trigger that is pushed; both parties agree that the term
encompasses both. The question is whether the statute is referring to the mechanical action of the trigger itself or
the shooter’s physical acting upon the trigger (regardless of the specific action the trigger requires in order to be
acted upon).
6We have interpreted other parts of § 5845(b). See, e.g., Dodson, 519 F. App’x at 348-49 (discussing the
change of § 5845(b) from banning only a “combination” of parts under the Gun Control Act of 1968 to banning
“any” part as amended in 1986); United States v. Carter, 465 F.3d 658, 663-64 (6th Cir. 2006) (discussing whether
the defendant could be charged with possessing a machine gun under § 5845(b) due to his possession of machine
gun parts, if he was not charged with possessing a trigger mechanism); One TRW, Model M14, 7.62 Caliber Rifle,
441 F.3d at 419-25 (interpreting the meaning of “designed to shoot” and “can be readily restored” as used in
§ 5845(b)).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 31

Final Rule as a permissible interpretation.7 Gun Owners of Am., 363 F. Supp. 3d at 832. But
having determined that Chevron deference is not applicable in this context, we must decide the
best meaning of the statute without putting a thumb on the scale in the government’s favor.

“When interpreting the words of a statute, contemporaneous dictionaries are the best
place to start.” Helson, 930 F.3d at 802. We begin by looking to dictionaries contemporaneous
with the passage of the Gun Control Act of 1968.8 However, the dictionary definition of
“function” lends support to both interpretations. See Webster’s Third New International
Dictionary 920-21 (1967) (defining “function” as an “action”); Webster’s Seventh New
Collegiate Dictionary 338 (1967) (defining “function” as “the acts or operations expected of a
. . . thing” and the “characteristic action of a . . . manufactured or created thing”). That is to say,
because “function” means “action,” dictionaries alone do not reveal whether the statute is
referring to the mechanical “act” of the trigger’s being depressed or the physical “act” of the

7The D.C. Circuit likewise found the ATF’s interpretation to be “permissible,” though it did not need to
decide whether the ATF’s interpretation was the best interpretation because the court was also operating within the
Chevron-deference framework. See Guedes, 920 F.3d at 31-32; see also Akins, 312 F. App’x at 200 (finding that the
ATF’s interpretation of “single function of the trigger” meaning “single pull of the trigger” was consistent enough
with the statute’s text and legislative history so as to survive the APA’s arbitrary-and-capricious standard).
8We note that the Final Rule, the district court, and the D.C. Circuit all relied on dictionaries
contemporaneous with the passage of the Firearms Act of 1934. See Final Rule, 83 Fed. Reg. at 66,519; Gun
Owners of Am., 363 F. Supp. 3d at 831-32; Guedes, 920 F.3d at 29. However, with the Gun Control Act of 1968,
Congress chose to redraft 26 U.S.C. § 5845(b) in its entirety—albeit with nearly identical language to the National
Firearms Act of 1934. And because we interpret the statute’s meaning relying on dictionaries contemporaneous
with the provision’s most recently enacted language, in this case we must rely on dictionaries contemporaneous with
the Gun Control Act of 1968. See Sandifer v. U.S. Steel Corp., 571 U.S. 220, 226-28 (2014) (relying on the 1950
meaning of “clothes” because Congress amended the Fair Labor Standards Act in 1949, eleven years after its initial
passage).
To be sure, the 1986 Gun Owners’ Protection Act amended some language of § 5845(b), but Congress left
the first part of the statutory definition of a machine gun untouched (including the terms “single function of the
trigger” and “automatically”). See Pub. L. 99-308, 100 Stat. 449 (amending 18 U.S.C. §§ 921-29). Moreover, the
1986 Act expressly detailed which specific parts of § 5845(b) were being amended as opposed to the 1968 Act’s
enacting a new (albeit similarly worded) definition. Because these terms were not amended, reenacted, or otherwise
affected by the 99th Congress in 1986, we will not look to dictionaries from 1986 to determine their meaning. See
United States v. Melvin, 948 F.3d 848, 852 n.1 (7th Cir. 2020) (explaining that the court will rely on 1984
dictionaries for a 1984 statute that had since been amended because “the relevant portion of the statute remains the
same”).
Instead, we rely on 1968 dictionaries for assistance in determining the meaning of “single function of the
trigger,” though we do not see a material change in the meaning of “function” from 1934 to 1968 to 1986. Cf. 4
Oxford English Dictionary 602 (1933) (defining “function” as “mode of action”); Webster’s New International
Dictionary 876 (1933) (defining “function” as “natural . . . action”); Webster’s Third New International Dictionary
920-21 (1968) (defining “function” as an “action”); Webster’s Third New International Dictionary 920-21 (1986)
(same).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 32

shooter’s pulling the trigger. See Guedes, 920 F.3d at 29 (finding that “function” means “action”
but that “the text is silent on the crucial question of which perspective is relevant”).

We next consider the phrase in the context of the rest of the statute to see if that
illuminates which meaning of “function” Congress intended when drafting § 5845(b). See
Helson, 930 F.3d at 803-04 (after reviewing contemporaneous dictionaries, next considering “the
context provided by the rest of the statute” as “[a]nother tool of interpretation”). “Statutory
interpretation is a ‘holistic endeavor’—the structure and wording of other parts of a statute can
help clarify the meaning of an isolated term.” Id. at 803 (quoting United Sav. Ass’n v. Timbers of
Inwood Forests Assocs., Ltd., 484 U.S. 365, 371 (1988)). Here, the statutory context weighs
heavily in Plaintiffs-Appellants’ favor.

First, the phrase plainly refers only to the “single function of the trigger,” § 5845(b)
(emphasis added), not “the trigger finger.” And if “function” is understood to mean “action,”
then the most natural reading of § 5845(b) would not be to read “single action of the trigger” to
mean “single action of the trigger finger.” Rather the best, most natural reading would be that
§ 5845(b) refers to the trigger itself.

Second, this interpretation is further supported by the fact that the rest of § 5845(b)’s
statutory definition of a machine gun describes the firearm, not the shooter, the shooter’s body
parts, or the shooter’s actions. Indeed, the entire definition focuses exclusively on the firearm’s
design and capability. At no point does the definition mention the shooter or the shooter’s
actions. Nothing in the statute suggests that the phrase “single function of the trigger” refers to
the shooter’s pulling the trigger rather than the trigger itself.

Third, the Final Rule’s interpretation that “single function of the trigger” means “single
pull of the trigger and analogous motions,” Final Rule, 83 Fed. Reg. at 66,554, necessarily refers
to the trigger and not to the shooter or the shooter’s act of pulling. The ATF’s Rule does not
interpret the phrase to mean “single pull by the trigger finger” or “the shooter’s single pull of the
trigger.” Instead, as with the statute, the Final Rule’s language refers only to the “trigger” itself
without any mention of the shooter or the shooter’s actions.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 33

Finding that “function” refers to the mechanical process, we conclude that a bump stock
cannot be classified as a machine gun under § 5845(b). We recognize that a bump stock
increases a semiautomatic firearm’s rate of firing, possibly to a rate nearly equal to that of an
automatic weapon. With a bump stock attached to a semiautomatic firearm, however, the trigger
still must be released, reset, and pulled again before another shot may be fired. A bump stock
may change how the pull of the trigger is accomplished, but it does not change the fact that the
semiautomatic firearm shoots only one shot for each pull of the trigger. Guedes, 920 F.3d at 48
(Henderson, J., concurring in part and dissenting in part). This remains true regardless of
whether the shooter’s finger is stationary (when operating a bump-stock-attached semiautomatic
firearm) or is moving (when operating a semiautomatic firearm without a bump stock). And it
likewise remains true regardless of whether the physical force depressing the trigger comes from
the shooter’s trigger finger’s pushing the trigger or the recoil energy of the firearm’s pushing the
trigger against the shooter’s trigger finger. With or without a bump stock, a semiautomatic
firearm is capable of firing only a single shot for each pull of the trigger and is unable to fire
again until the trigger is released and the hammer of the firearm is reset.

Indeed, to the extent that the Supreme Court has spoken on the meaning of § 5845(b), its
interpretation is supportive of the interpretation we adopt today. See Staples v. United States,
511 U.S. 600, 602 n.1 (1994) (“As used here, the terms ‘automatic’ and ‘fully automatic’ refer to
a weapon that fires repeatedly with a single pull of the trigger. That is, once its trigger is
depressed, the weapon will automatically continue to fire until its trigger is released or the
ammunition is exhausted. Such weapons are ‘machineguns’ within the meaning of the Act.”).
The Supreme Court’s language may not necessarily foreclose the ATF’s interpretation. See
Guedes, 920 F.3d at 30 (finding that Staples does not “compel a particular interpretation of
‘single function of the trigger’”). But the Court’s focus on whether the “trigger is depressed”
and how many times the firearm is capable of firing until the “trigger is released” strongly
suggests that the Court understood § 5845(b) as referring to the mechanical process of the
depress-release-reset cycle of the trigger. See Staples, 511 U.S. at 602 n.1.

Given that the first bump-stock-type invention was not patented until well over a decade
after the most recent amendment to § 5845(b), it would be impossible to say definitively whether
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 34

the 90th Congress in 1968 or the 99th Congress in 1986 would or would not have intended to ban
bump stocks as automatic weapons. “But the fact that Congress might have acted with greater
clarity or foresight does not give courts a carte blanche to redraft statutes in an effort to achieve
that which Congress is perceived to have failed to do.” United States v. Locke, 471 U.S. 84, 95
(1985). And the statutory definition of a machine gun, as amended, excludes bump stocks
because bump-stock devices do not fundamentally change the line Congress drew to distinguish
automatic firearms from semiautomatic ones.

Congress could amend the statute tomorrow to criminalize bump-stock ownership, if it so
wished; indeed, some states have done just that. See, e.g., DEL. CODE ANN. tit. 11 § 1444(a)(6)
(2020); R.I. GEN. LAWS ANN. § 11-47-8(d) (2020); WASH. REV. CODE ANN. §§ 9.41.010(3),
9.41.190, 9.41.220 (2020); N.Y. PENAL LAW §§ 265.00(26-27); 265.10, 265.01-c (2019); NEV.
REV. STAT. ANN. § 202.274 (2019); CAL. PENAL CODE §§ 16930, 32900 (2019); MD. CODE
ANN., CRIM. LAW §§ 4-301(f), 4-305.1, 4-306 (2019); N.J. STAT. ANN. §§ 2C:39-3(l), 39-9(j)
(2019); FLA. STAT. ANN. § 790.222 (2018); HAW. REV. STAT. § 134-8.5 (2018); MASS. GEN.
LAWS ANN. ch. 140, §§ 121, 131 (2018); VT. STAT. ANN. tit. 13, § 4022 (2018).

But as judges, we cannot amend § 5845(b). See Henson v. Santander Consumer USA
Inc., 137 S. Ct. 1718, 1726 (2017) (“[T]he proper role of the judiciary . . . [is] to apply, not
amend, the work of the People’s representatives.”). And neither can the ATF. See Dodson,
519 F. App’x at 349 (“The ATF does not have the ability to redefine or create exceptions to
Congressional statutes.”). This is because the separation of powers requires that any legislation
pass through the legislature, no matter how well-intentioned or widely supported the policy
might be. See INS v. Chadha, 462 U.S. 919, 954 (1983) (“Amendment and repeal of statutes, no
less than enactment, must conform with Art. I.”). To allow otherwise would put individual
liberty at serious risk. Id. at 950 (citing THE FEDERALIST NO. 51 (James Madison or Alexander
Hamilton)).

In sum, based on the text and context of § 5845(b), and further supported by the Supreme
Court’s interpretation in Staples, we conclude that the phrase “the single function of the trigger”
refers to the mechanical process of the trigger, not the shooter’s pulling of the trigger.
Consequently, a bump stock cannot be classified as a machine gun under § 5845(b).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 35

B. “Automatically”

Our holding that a bump stock does not fall within the statutory definition of a machine
gun because a bump stock does not cause a firearm to fire more than one shot by a single
function of the trigger is sufficient to resolve this appeal. Consequently, we need not address or
decide whether the ATF or Plaintiffs-Appellants have the better interpretation of “automatically”
as used in 26 U.S.C. § 5845(b).9

V. Remaining Preliminary Injunction Factors

Having determined that Plaintiffs-Appellants are likely to prevail on the merits, we
address the three remaining factors of a preliminary injunction: (1) whether Plaintiffs-Appellants
will suffer irreparable injury without an injunction; (2) whether the issuance of a preliminary
injunction would cause substantial harm to others; and (3) whether the issuance of a preliminary
injunction would serve the public interest. Leary, 228 F.3d at 736 (citation omitted). The final
two factors—assessing the harm to others and weighing the public interest—“merge when the
Government is the opposing party.” Wilson, 961 F.3d at 844 (quoting Nken, 556 U.S. at 435).
The government conceded in the district court that Plaintiffs-Appellants would suffer irreparable
harm without an injunction. Gun Owners of Am., 363 F. Supp. 3d at 833. And, as we stated in
Part III.D.1, the Final Rule will cause bump-stock owners to either surrender or destroy their
devices (the ATF estimates that the loss of property will exceed $100 million, see Final
Rule, 83 Fed. Reg. at 66,515) or face serious fines and imprisonment. The ATF claims that the

9Courts have identified varying interpretations of “automatically” as used in § 5845(b). Compare
Aposhian, 958 F.3d at 986-88 (finding that the term “automatically” “does not require there be no human
involvement”), and Guedes, 920 F.3d at 170-72 (finding that “the term [automatically] can be read to require only
that there be limited human involvement to bring about more than one shot”), with Aposhian, 958 F.3d at 996-98
(Carson, J., dissenting) (accepting the ATF’s interpretation of “automatically” as meaning “self-acting” and “self-
regulating,” but finding that the terms “are self-explanatory—they exclude any manual human involvement by their
very definitions,” and explaining that “nonmechanical bump stocks require manual human involvement at all times
as part of their underlying mechanisms”), and Guedes, 920 F.3d at 43-45 (Henderson, J., concurring in part and
dissenting in part) (concluding that the ATF’s interpretation “misreads” the term “automatically” because the
“constant forward pressure with the non-trigger hand” necessary for the bump-stock-attached firearm to operate
means that something more than just a single function of the trigger is needed to fire multiple shots, and because the
ATF’s interpretation fails to “maintain[] the longstanding distinction between ‘automatic’ and ‘semiautomatic’ in
the firearms context”). See also Aposhian, 958 F.3d at 992 n.1 (Carson, J., dissenting) (explaining that mechanical
bump stocks, such as the Akins Accelerator, use internal springs instead of constant forward pressure to propel the
firearm forward and thus function differently from nonmechanical bump stocks, which require constant forward
pressure).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 36

bump-stock ban will further public safety, which may be true, but that claim is undercut by the
ATF’s admission that “there may not have been a number of violent acts committed with bump
stocks,” notwithstanding the half-million bump-stock devices in circulation across the country.
Final Rule, 83 Fed. Reg. at 66,538. Without an injunction, Plaintiffs-Appellants will suffer
immediate, quantifiable, and serious irreparable harm, while the impact of the issuance of an
injunction on public safety is only speculative based on the evidence that the ATF has provided
to us and the public. And Plaintiffs-Appellants are likely to prevail on the merits. Weighing
these factors together, we hold that the district court should have granted Plaintiffs-Appellants a
preliminary injunction and, therefore, we reverse the district court’s judgment.

However, we do not decide the scope of the injunction, except to say that the scope may
not exceed the bounds of the four states within the Sixth Circuit’s jurisdiction and, of course,
encompasses the parties themselves. Though we disagree with the ATF’s position, the ATF
prevailed before the Tenth Circuit, as well as the D.C. Circuit Court, from which decision the
Supreme Court denied certiorari. See Guedes, 920 F.3d at 6, cert. denied 140 S. Ct. 789 (2020).
If we were to permit a universal injunction (also frequently called a “nationwide injunction”), we
would create an absurd situation in which the ATF must prevail in every single case brought
against the Final Rule in order for its interpretation to prevail. We do not think that it is within
our authority to overrule the decision of a sister circuit (or for a district court within our circuit to
do so). See Nixon, 76 F.3d at 1388 (holding that we are not bound by “the views of our sister
circuits”).

While this will create a circuit split on the meaning of § 5845(b), there is value in having
legal issues “percolate” in the lower courts. See CASA de Md., Inc. v. Trump, 971 F.3d 220, 260
(4th Cir. 2020) (“[N]ationwide injunctions limit valuable ‘percolation’ of legal issues in the
lower courts. . . . And the value of percolation is at its apex where, as here, ‘a regulatory
challenge involves important or difficult questions of law.’” (quoting L.A. Haven Hospice, Inc. v.
Sebelius, 638 F.3d 644, 664 (9th Cir. 2011)). The Supreme Court has noted that it is often
“preferable to allow several courts to pass on a given [issue] in order to gain the benefit of
adjudication by different courts in different factual contexts.” Califano v. Yamasaki, 442 U.S.
682, 702 (1979). Indeed, Justice Gorsuch, in his concurrence in the denial of certiorari for the
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 37

Guedes case, stated that: “[O]ther courts of appeals are actively considering challenges to the
same regulation. Before deciding whether to weigh in, we would benefit from hearing their
considered judgments[.]” Guedes, 140 S. Ct. at 791 (Gorsuch, J., concurring in denial of cert.).
The short-term uncertainty and disunity created by percolation is justified by its producing a
more thorough review of the issue, which in turn should provide a stable, more accurate body of
law in the long run. See CASA de Md., 971 F.3d at 260 (“Nationwide injunctions limit dialogue
in the lower courts, favoring quick and uniform answers to the more deliberate—and likely more
accurate—method of doctrinal development that is intended under our judiciary’s very design.”).
For these reasons, we would not purport to issue a universal or nationwide injunction, and we
otherwise leave the issue of the scope of the injunction to be briefed by the parties and decided
by the district court.

VI. Conclusion

Consistent with our precedent and mandated by separation-of-powers and fair-notice
concerns, we hold that an administering agency’s interpretation of a criminal statute is not
entitled to Chevron deference. Consequently, the district court erred by finding that the ATF’s
Final Rule, which interpreted the meaning of a machine gun as defined in 26 U.S.C. § 5845(b),
was entitled to Chevron deference. And because we find that “single function of the trigger”
refers to the mechanical process of the trigger, we further hold that a bump stock cannot be
classified as a machine gun because a bump stock does not enable a semiautomatic firearm to
fire more than one shot each time the trigger is pulled. Accordingly, we find that Plaintiffs-
Appellants are likely to prevail on the merits and that that their motion for an injunction should
have been granted.
Therefore, we REVERSE the judgment of the district court and REMAND for
proceedings consistent with this opinion.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 38

_________________

DISSENT
_________________

WHITE, Circuit Judge, dissenting. I respectfully disagree with the majority’s conclusion
that Chevron never applies to laws with criminal applications. The Supreme Court has applied
Chevron in the criminal context in three binding decisions—Chevron itself, Babbitt, and
O’Hagan1—and has never purported to overrule those cases. Although comments in subsequent
decisions may create tension with these cases, they remain binding. Thus, I would apply
Chevron. And because the statutory phrase here is ambiguous and the ATF’s interpretation of
that phrase is reasonable, it is entitled to deference under Chevron.

I. Chevron Applies

Chevron applies here. First, the ATF’s Bump-Stock Rule is the type of “legislative” rule
that usually triggers Chevron’s two-step framework. Second, that framework is not waivable.
Third, the framework applies even though the rule carries criminal consequences. And fourth,
the majority’s normative arguments to the contrary are not persuasive.

A. The ATF’s Rule is “Legislative”

The Administrative Procedure Act draws a “central distinction” between legislative and
interpretive rules. Azar v. Allina Health Servs., 139 S. Ct. 1804, 1814 (2019) (quoting Chrysler
Corp. v. Brown, 441 U.S. 281, 301 (1979)). That “distinction centrally informs the applicability
of Chevron.” Guedes v. Bureau of Alcohol, Tobacco, Firearms, and Explosives, 920 F.3d 1, 17
(D.C. Cir. 2019). Legislative rules typically trigger Chevron, Atrium Med. Ctr. v. U.S. Dep’t of
Health & Hum. Servs., 766 F.3d 560, 566 (6th Cir. 2014), while interpretive rules, in general,
“enjoy no Chevron status as a class,” United States v. Mead Corp., 533 U.S. 218, 232 (2001).

Legislative rules “have the ‘force and effect of law.’” Tenn. Hosp. Ass’n v. Azar,
908 F.3d 1029, 1042 (6th Cir. 2018) (quoting Perez v. Mortg. Bankers Ass’n, 575 U.S. 92, 96

1Chevron, U.S.A., Inc. v. Nat. Res. Def. Council, Inc., 467 U.S. 837 (1984); Babbitt v. Sweet Home Chapter
of Cmtys. for a Great Or., 515 U.S. 687 (1995); United States v. O’Hagan, 521 U.S. 642 (1997).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 39

(2015)). “[I]nterpretive rules do not,” id., and are instead meant only “‘to advise the public of
the agency’s construction of the statutes and rules which it administers,’” Shalala v. Guernsey
Mem’l Hosp., 514 U.S. 87, 99 (1995) (citation omitted). Legislative rules must be promulgated
through the APA’s notice-and-comment procedures, but interpretive rules need not be. Tenn.
Hosp., 908 F.3d 1042; 5 U.S.C. § 553(b).

A rule is “legislative” if it “‘intends to create new law, rights, or duties.’” Tenn. Hosp.,
908 F.3d at 1042 (citation omitted). A rule is “interpretive” if it instead “‘simply states what the
administrative agency thinks the statute means, and only reminds affected parties of existing
duties.’” Id. (citation omitted). “Because interpretive rules cannot ‘effec[t] a substantive change
in the regulations,’ a rule that ‘adopt[s] a new position inconsistent with any’” of the agency’s
existing regulations “is necessarily legislative.” Id. (alterations in original) (quoting Guernsey
Mem’l Hosp., 514 U.S. at 100). Congress’s authorization of an agency to “proceed through
notice-and-comment rulemaking” is a “‘very good indicator’ that Congress intended” rules
passed through that procedure “to carry the force of law.” Encino Motorcars, LLC v. Navarro,
136 S. Ct. 2117, 2125 (2016).

The ATF’s rule is “legislative.” See Bump-Stock-Type Devices, 83 Fed. Reg. 66,514
(Dec. 26, 2018). To start, it went through formal notice-and-comment rulemaking, id. at 66,517,
a strong sign that the agency intended to speak with the force of law, Encino Motorcars, 136 S.
Ct. at 2122, 2125. It also adopted a position inconsistent with previous interpretations of
“machinegun.” From 2008 to 2017, several ATF classification letters said that certain
bump-stock devices were not “machineguns” because they “did not rely on internal springs or
similar mechanical parts to channel recoil energy.” 83 Fed. Reg. at 66,516. The Bump-Stock
Rule treats these devices as “machineguns,” id. at 66,531, creating new obligations that
previously did not exist, see id. at 66,516 (noting that previously, “[i]ndividuals . . . have been
able to legally purchase these devices”). Although the 2008-2017 interpretations were issued
through classification letters, not legislative regulations, this change still strongly suggests that
the ATF meant to create new rights or duties. Cf. Tenn. Hosp., 908 F.3d at 1042.

Further, as the D.C. Circuit recently observed, “[a]ll pertinent indicia of agency intent
confirm that the Bump-Stock Rule is a legislative rule.” Guedes, 920 F.3d at 18. The rule’s text
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 40

evinces an intent to change rights and obligations. At several points, it speaks in terms of
prospective, post-enactment changes in the law. See, e.g., 83 Fed. Reg. at 66,514 (warning that
bump-stock devices “will be prohibited when this rule becomes effective”); id. at 66,523
(“Anyone currently in possession of a bump-stock-type device is not acting unlawfully unless
they fail to relinquish or destroy their device after the effective date of this regulation.”). The
rule also expressly invoked Chevron, id. at 66,527, and relied on several statutory provisions
delegating legislative authority to the Attorney General, id. at 66,515, 66,527 (citing 18 U.S.C.
§ 926(a); 26 U.S.C. §§ 7801(a)(2)(A) & 7805(a)); see also Guedes, 920 F.3d at 18-19 (reasoning
that the ATF’s discussion of Chevron and invocation of these statutory provisions strongly signal
that the ATF meant to use its legislative authority). “When an agency acts pursuant to an express
delegation that directs the agency to issue regulations or set permissible standards, the resulting
rule is generally . . . considered to be legislative.” Tenn. Hosp., 908 F.3d at 1043. The ATF did
that here, and its rule is legislative.

Because the rule is legislative, it is the type of rule to which Chevron’s two-step
framework typically applies. We apply Chevron when “Congress delegated authority to the
agency generally to make rules carrying the force of law” and “the agency interpretation” in
question “was promulgated in the exercise of that authority.” Mead, 533 U.S. at 226-27. Both
prerequisites are satisfied here. Congress expressly delegated rulemaking authority to the
Attorney General, see 18 U.S.C. § 926(a); 26 US.C. §§ 7801(a)(2)(A) & 7805(a), and the ATF
exercised that authority through notice-and-comment rulemaking, see Encino Motorcars, 136 S.
Ct. at 2125 (“When Congress authorizes an agency to proceed through notice-and-comment
rulemaking, that ‘relatively formal administrative procedure’ is a ‘very good indicator’ that
Congress intended the regulation to carry the force of law, so Chevron should apply.” (quoting
Mead, 533 U.S. at 229-30)).2 The Bump-Stock Rule is “firmly within Chevron’s domain.”
Guedes, 920 F.3d at 21.

2As the Fourth Circuit recently put it, “[w]hen an agency’s interpretation ‘derives from notice-and-
comment rulemaking,’ it will ‘almost inevitably receive Chevron deference.’” Sierra Club v. U.S. Army Corps of
Eng’rs, 909 F.3d 635, 644 (4th Cir. 2018) (citation omitted). We have frequently said the same. See, e.g., Zurich
Am. Ins. Grp. v. Duncan ex rel. Duncan, 889 F.3d 293, 301-02 (6th Cir. 2018) (“Section 718.305(b)(2) was adopted
after notice-and-comment rulemaking, and therefore is analyzed under the two-step framework that the Supreme
Court articulated in Chevron[.]” (citations omitted)); Sierra Club v. Env’t Prot. Agency, 793 F.3d 656, 665 (6th Cir.
2015) (“Where petitioner challenges an agency’s interpretation of a statute promulgated after notice-and-comment
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 41

But two issues remain. First, Plaintiffs argue that the government has “waived” Chevron.
Second, the majority concludes that Chevron does not apply in criminal contexts. Neither issue
precludes Chevron deference because Chevron is not waivable, and the Supreme Court has
applied Chevron to legislative rules with criminal applications.

B. Chevron Cannot Be Waived

The government disclaims any reliance on Chevron. See Appellees’ Br. at 15-16
(“Plaintiffs’ extended discussion of Chevron deference . . . likewise fails to advance their claims.
Deference is unnecessary where, as here, the Rule properly interprets the statute . . . . The
government thus does not rely on Chevron deference, but if this Court were to employ that
framework, plaintiffs would still not be entitled to a preliminary injunction.”). Plaintiffs argue
that the government waived Chevron here. The D.C. Circuit addressed a similar claim in
Guedes, 920 F.3d at 21-23, and persuasively explained that Chevron may not be waived in this
context.3

There are several problems with concluding that Chevron can be waived. To start,
Chevron is not a right or privilege that belongs to a party; it is a standard of review, as we have
repeatedly recognized.4 It is well-established that a “‘party cannot waive the proper standard of
review by failing to argue it.’” Hubbell v. FedEx SmartPost, Inc., 933 F.3d 558, 571 (6th Cir.

rulemaking, we assess the lawfulness of the interpretation under the familiar two-step Chevron framework.”); Sierra
Club v. ICG Hazard, LLC, 781 F.3d 281, 287 (6th Cir. 2015) (“[W]e defer to the agency’s interpretation, provided
that interpretation was promulgated via notice-and-comment rulemaking or a formal adjudication . . . .” (citations
omitted)); Spectrum Health Continuing Care Grp. v. Anna Marie Bowling Irrevocable Trust Dated June 27, 2002,
410 F.3d 304, 319 (6th Cir. 2005) (“[A]gency action resulting from notice-and-comment rule-making or formal
adjudications is entitled to judicial deference.” (citing Mead, 533 U.S. at 230)); Owensboro Health, Inc. v. Sec’y of
Health & Hum. Servs., 706 F. App’x 302, 306 (6th Cir. 2017) (“When an agency engages in statutory interpretation
with the force of law, such as through notice-and-comment rulemaking, we afford the agency deference.” (citing
Chevron, 467 U.S. 837 (1984)).
3The Supreme Court has not yet addressed this issue. At least one Justice disagrees with the waiver
analysis in Guedes. See Guedes v. Bureau of Alcohol, Tobacco, Firearms & Explosives, 140 S. Ct. 789, 790 (2020)
(Gorsuch, J., concurring in denial of certiorari) (arguing that the D.C. Circuit’s conclusion on Chevron waiver “was
mistaken”).
4See, e.g., Keeley v. Whitaker, 910 F.3d 878, 885 (6th Cir. 2018) (describing Chevron as a “standard of
review”); Nat’l Truck Equip. Ass’n v. Nat. Highway Traffic Safety Admin., 711 F.3d 662, 668 (6th Cir. 2013)
(same); Estate of Gerson v. Comm’r., 507 F.3d 435, 438 (6th Cir. 2007) (same); TNS, Inc. v. NLRB, 296 F.3d 384,
393 (6th Cir. 2002) (same); United States v. Hopper, 941 F.2d 419, 421-22 (6th Cir. 1991) (same).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 42

2019) (citation omitted). “Such a determination remains for this court to make for itself.” K&T
Enters., Inc. v. Zurich Ins. Co., 97 F.3d 171, 175 (6th Cir. 1996). That same principle applies to
Chevron.

Allowing Chevron to be waived would also contravene “basic precepts of administrative
law.” Guedes, 920 F.3d at 22. When a legislative rule is passed through notice-and-comment
rulemaking, an agency may not reverse that rule without once more undergoing the notice-and-
comment process. See Perez, 575 U.S. at 101 (“[A]gencies [must] use the same procedures
when they amend or repeal a rule as they used to issue the rule in the first instance.”). Likewise,
if an agency seeks to reverse its position, that decision will be reviewed for arbitrariness.
5 U.S.C. § 706(2)(A). A “waiver regime” would allow for an end-run around these
requirements:

A waiver regime, moreover, would allow an agency to vary the binding nature of
a legislative rule merely by asserting in litigation that the rule does not carry the
force of law, even though the rule speaks to the public with all the indicia of a
legislative rule. Agency litigants then could effectively amend or withdraw the
legal force of a rule without undergoing a new notice-and-comment rulemaking.
That result would enable agencies to circumvent the Administrative Procedure
Act’s requirement “that agencies use the same procedures when they amend or
repeal a rule as they used to issue the rule in the first instance.” [Perez, 575 U.S.
at 101]. And an agency could attempt to secure rescission of a policy it no longer
favors without complying with the Administrative Procedure Act, or perhaps
could avoid the political accountability that would attend its own policy reversal
by effectively inviting courts to set aside the rule instead.

Guedes, 920 F.3d at 22-23.

Thus, we must independently determine whether Chevron applies.5

5Our decision in Commodity Futures Trading Comm’n v. Erskine, 512 F.3d 309, 314 (6th Cir. 2008) does
not compel a contrary result. In Erskine, the CFTC sued the defendants under the Commodity Exchange Act, which
gave the CFTC jurisdiction over “futures contracts” involving certain foreign exchange transactions. Id. at 310-13.
The key issue was whether the statutory term “futures contracts” encompassed the type of transaction at issue in the
CFTC’s lawsuit. Id. at 313. The CFTC never issued any type of rule or formal adjudication defining the term, and
in the district court, it made no Chevron argument. Id. at 314. But on appeal, its lawyers argued that their
interpretation of the term was entitled to Chevron deference. Id. The defendants responded with three arguments:
(1) the CFTC “waived any reliance on Chevron deference by failing to raise it to the district court”; (2) Congress
never delegated to the CFTC the power to define the term, and Chevron depends on delegation; and (3) the CFTC
had never defined the term in “a rule-making or in an adjudication, which would provide for Chevron deference, but
has merely asserted its preferred definition during the course of litigation,” a position that could not garner Chevron
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 43

C. Chevron and Criminal Laws

The majority concludes that Chevron never applies to laws with criminal applications.
It first determines that the relevant caselaw leaves the question open and then puts forth three
normative reasons why Chevron ought not apply. I disagree with the majority’s discussion of the
caselaw and with its proffered rationales.

1. The Caselaw

To start, Chevron itself involved an agency interpretation that had criminal implications.
The issue in Chevron was the meaning of the term “stationary source” in the Clean Air Act.
467 U.S. at 840. Under the statutory regime, private parties in certain states had to obtain a
permit when they added a new “major stationary source” of air pollution. Id. The EPA issued a
regulation providing that industrial plants did not add a new “source” when they added new
pieces of pollution-emitting equipment unless the alteration increased the total emissions in the
plant. Id. The National Resources Defense Council sued, arguing that a new permit was needed
whenever a new pollution-emitting device emitting over 100 tons of pollutants was added. Id. at
841 n.3, 859. At the time, knowing violation of the permit requirement was punishable by daily
$25,000 fines and imprisonment for up to a year. 42 U.S.C. § 7502(a)(1), (b)(6) (1982); id.
§ 7413(c)(1) (1982). Still, the Court applied deference. Chevron, 467 U.S. at 866.

In United States v. O’Hagan, 521 U.S. 642, 667, 673 (1997), a criminal case, the Court
applied Chevron deference to an SEC regulation that carried criminal penalties. There, a lawyer
was convicted of seventeen counts of fraudulent trading in connection with a tender offer, in
violation of § 14(e) of the Exchange Act and SEC Rule 14e–3(a), after engaging in several stock
transactions based on material non-public information he obtained through his firm’s assistance

deference due to lack of “administrative formality.” Id. (citations omitted). In a single sentence, we stated that we
agreed with the defendants on each point: “We agree with [defendants] on each of [their] points and conclude that
the CFTC is not entitled to Chevron deference on this issue.” Id.
Although Erskine appears to voice agreement with the suggestion that Chevron arguments may be
forfeited, it offered no discussion on the issue. More importantly, the issue was not necessary to its holding and thus
constituted dictum. See Freed v. Thomas, 976 F.3d 729, 738 (6th Cir. 2020) (“[D]ictum is anything ‘not necessary
to the determination of the issue on appeal.’” (quoting United States v. Swanson, 341 F.3d 524, 530 (6th Cir.
2003))). The Erskine court found that the prerequisite to Chevron—congressional delegation—was absent, and it
also found that the agency had not taken any actions that could have triggered Chevron to begin with. Thus, the
panel’s unarticulated acceptance of the defendant’s waiver argument was not necessary to its conclusion.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 44

with a tender offer. Id. at 647-49. The Supreme Court rejected his challenge to the scope of
Rule 14e–3(a), and applied Chevron to the rule, despite its clear criminal applications. See id. at
673 (“Because Congress has authorized the Commission, in § 14(e), to prescribe legislative
rules, we owe the Commission’s judgment ‘more than mere deference or weight.’. . . [W]e must
accord the Commission’s assessment ‘controlling weight unless [it is] arbitrary, capricious, or
manifestly contrary to the statute.’” (second alteration in original) (quoting Chevron, 467 U.S. at
844) (other citation omitted)).6

6The majority suggests that O’Hagan did not apply Chevron deference, yet it also recognizes that the Court
(1) cited Chevron, (2) while citing Chevron, recognized that the agency’s legislative rule was entitled to “more than
mere deference or weight,” and (3) applied deference to the rule. Majority Op. at 13-14. The O’Hagan court cited
Chevron, held that the SEC’s regulation was entitled to “controlling weight” unless it was “manifestly contrary to
the statute,” determined that the regulation was not contrary to the statute, and applied deference. 521 U.S. at 673.
If that does not count as applying Chevron deference, what does? See also Mead, 533 U.S. at 230 & n.12 (stating
that the “overwhelming number of our cases applying Chevron deference have reviewed the fruits of notice-and-
comment rulemaking or formal adjudication,” and listing O’Hagan among the “rulemaking cases” where Chevron
deference applied); Valenzuela Gallardo v. Barr, 968 F.3d 1053, 1060 (9th Cir. 2020) (noting that the Court
“grant[ed] Chevron deference” in O’Hagan); Guedes, 920 F.3d at 24 (same); Thomas W. Merrill & Kristin E.
Hickman, Chevron’s Domain, 89 GEO. L.J. 833, 874 n.220 (2001) (same).
The majority also tries to distinguish O’Hagan on the basis that it did not involve a purely criminal statute.
See Majority Op. at 14. (“While O’Hagan used the word ‘deference,’ it cannot be read to support the proposition
that the agency’s interpretation of a criminal statute receives Chevron deference.” (emphasis in original)). This
point relies on the assumption that the ATF’s Bump-Stock Rule only interpreted a purely criminal statute.
Throughout its opinion, the majority appears to repeatedly make this assumption. See, e.g., id. at 13 (“While Babbitt
certainly mentioned deference, it did not hold that an agency’s interpretation of a criminal statute is entitled to
Chevron deference . . . .”); id. at 15 (“[W]e have never held that Chevron deference applies to an agency’s
interpretation of a purely criminal statute, such as the ban on possessing a machine gun in 18 US.C. § 922(o).”).
That assumption is incorrect. Although Congress, in 1986, criminally banned private individuals from possessing
machineguns not already lawfully possessed before May 19, 1986, 18 U.S.C. § 922(o), the Bump-Stock Rule does
not purport to interpret this criminal provision. Rather, it interprets the word “machinegun” in the definition section
of 26 U.S.C. § 5845(b)—a definition that has both civil and criminal applications. See Guedes, 920 F.3d at 40 & n.7
(Henderson, J., concurring in part and dissenting in part) (“[T]he 26 U.S.C. § 5845(b) definition of ‘machinegun’
has both civil and criminal enforcement implications.”); Aposhian v. Barr, 958 F.3d 969, 982 (10th Cir. 2020) (the
ATF’s bumpstock regulation “carrie[s] both civil and criminal implications”); id. at 998-99 (Carson, J., dissenting)
(same). For example, § 922(o)’s criminal ban has exceptions for those making transfers “under the authority of” any
department or agency of the United States. 18 U.S.C. § 922(o)(2)(A). This exception allows certain arms dealers to
possess and transfer machineguns when they intend to sell them to police departments or government agencies. See
27 C.F.R. § 179.105 (discussing requirements for such dealers); United States v. Ardoin, 19 F.3d 177, 178 (5th Cir.
1994) (“In 1989, Ardoin also became a Colt distributor for law enforcement agencies. As a distributor, he was able
to sell to law enforcement agencies any class of weapons, including machineguns, as long as he maintained his Class
III license.”). For those exempted, § 5845(b)’s definition of “machinegun” carries civil implications as well. See
United States v. Hamblen, 239 F. App’x 130, 133 (6th Cir. 2007) (noting registered machinegun dealers must pay
“a special occupation tax”); Guedes, 920 F.3d at 40 & n.7 (Henderson, J., concurring in part and dissenting in part)
(pointing out that § 5845(b) has civil forfeiture and tax implications (citing 26 U.S.C. § 5872(a))).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 45

Neither Chevron nor O’Hagan addressed the interaction between Chevron and the rule of
lenity, but the Court squarely addressed the issue in Babbitt v. Sweet Home Chapter of Cmtys. for
a Great Or., 515 U.S. 687 (1995). There, the Court reviewed a regulation interpreting the
definition of the word “take” in the Endangered Species Act (ESA). Id. at 690. The ESA made
it illegal to “take” certain endangered species and attached criminal penalties for knowingly
doing so. Id. at 691-93, 696 n.9. Congress defined “take” to include several verbs, including
“harm,” but did not define what “harm” meant. Id. at 691. The Department of Interior
promulgated a regulation defining “harm” to include habitat degradation. Id. The plaintiffs
challenging the regulation argued that Chevron deference was improper because the ESA
included criminal penalties and, therefore, the rule of lenity should apply instead. Id. at 704
n.18. The Court rejected the argument and applied Chevron, despite the statute’s criminal
penalties. Id. at 703-04, 704 n.18.7

7As with O’Hagan, the majority asserts that Babbitt did not “discuss or decide whether Chevron applied
nor did it analyze the challenge using Chevron . . . .” Majority Op. at 13. That is incorrect. The Babbitt Court
reversed a split decision of the D.C. Circuit and vindicated the view of the dissenting appellate judge, who applied
Chevron. Babbitt, 515 U.S. at 694-95. From the start of its discussion onward—after recognizing that the ESA
failed to define the word “harm,” id. at 691—the Court framed the question as whether the Department of Interior’s
regulation was reasonable or permissible, a question that only makes sense if the Court was operating within
Chevron’s domain, see, e.g., id. at 696 n.9 (framing discussion by noting that the Court was “assessing the
reasonableness of the regulation”); id. at 697 (“The text . . . provides three reasons for concluding that the
Secretary’s interpretation is reasonable.” (emphasis added)); id. at 699 (noting that Congressional intent “supports
the permissibility of the Secretary’s ‘harm’ regulation” (emphasis added)); id. at 700 (noting that “the Secretary’s
definition of ‘harm’ is reasonable”); id. at 702 (stating that the regulation “permissively interprets” the word
“harm”). If any doubt was left, the Court cleared it on page 703 of the opinion, where it (1) recognized that
Congress had not “unambiguously” defined the word “harm” (Chevron Step One); (2) concluded that the DOI’s
interpretation was reasonable (Chevron Step Two); and (3) found it unnecessary to decide if the DOI’s interpretation
was the best one, because the fact that the interpretation was reasonable “suffice[d] to decide this case:”
We need not decide whether the statutory definition of “take” compels the Secretary’s
interpretation of “harm,” because our conclusions that Congress did not unambiguously manifest
its intent to adopt respondents’ view and that the Secretary’s interpretation is reasonable suffice to
decide this case. See generally Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc.,
467 U.S. 837 (1984).
Id. at 703. The Court repeated its invocation of Chevron when summarizing its conclusion at the end of the opinion.
Id. at 708. It was also clear to the three dissenting Justices that the majority was applying Chevron. See id. at 715
(Scalia, J., dissenting) (“In my view petitioners must lose—the regulation must fall—even under the test of
Chevron . . ., so I shall assume that the Court is correct to apply Chevron.”). Numerous subsequent courts and
commentators—including the Supreme Court—have recognized the same. See, e.g., Mead, 533 U.S. at 230 & n.12
(listing Babbitt as a case that “appl[ied] Chevron deference” to “the fruits of notice-and-comment rulemaking”);
Guedes, 920 F.3d at 27 (describing Babbitt as applying Chevron); Aposhian, 958 F.3d at 982 (same); see also
Valenzuela Gallardo, 968 F.3d at 1060; Competitive Enter. Inst. v. United States Dep’t of Transp., 863 F.3d 911,
915 n.4 (D.C. Cir. 2017); United States v. Atandi, 376 F.3d 1186, 1189 (10th Cir. 2004); United States v.
Kanchanalak, 192 F.3d 1037, 1047 n.17 (D.C. Cir. 1999); 33 WRIGHT AND MILLER, FEDERAL PRACTICE AND
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 46

Chevron, Babbitt, and O’Hagan all involved “legislative” regulations issued through
notice-and-comment rulemaking—i.e., regulations that trigger Chevron’s deferential
framework.8 In two 2014 cases that did not involve legislative regulations, the Court made
statements that could be taken to question whether Chevron applies in the criminal context.
United States v. Apel, 571 U.S. 359, 369 (2014) (“[W]e have never held that the Government’s
reading of a criminal statute is entitled to any deference.”); Abramski v. United States, 573 U.S.
169, 191 (2014) (“[C]riminal laws are for the courts, not for the Government, to construe. . . .
We think ATF’s old position no more relevant than its current one—which is to say, not relevant
at all. Whether the Government interprets a criminal statute too broadly (as it sometimes does)
or too narrowly (as the ATF used to . . .), a court has an obligation to correct its error.” (citing
Apel, 571 U.S. at 369)). These statements are at the core of the majority’s argument.

But Apel and Abramski never mention Chevron, Babbitt, or O’Hagan. Nor would they
be expected to because neither involved agency interpretations that would trigger Chevron to
begin with. Abramski involved informal agency guidance (ATF “circulars”). 573 U.S. at 183
n.8, 191; id. at 198 n.3, 202 (Scalia, J., dissenting). And Apel involved internal guidance
documents (DOJ manuals and Air Force JAG opinions) that the Court expressly noted were “not
intended to be binding.” 571 U.S. at 368.9 Thus, the Court’s statements in both cases do not
undermine Chevron’s applicability here because the agency guidance documents were not

PROCEDURE § 8427 n.12 (2d ed. Oct. 2020) (describing Babbitt as “applying Chevron deference to the Secretary’s
definition of ‘take’ under the Endangered Species Act”); William N. Eskridge & Lauren E. Baer, The Continuum of
Deference: Supreme Court Treatment of Agency Statutory Interpretations From Chevron to Hamdan, 96 GEO. L.J.
1083, 1135-36 n.178 (2008) (listing Babbitt as an example of a “prominent Chevron case[]”); Note, Justifying the
Chevron Doctrine: Insights From the Rule of Lenity, 123 HARV. L. REV. 2043, 2062 (2010) (“In a later case,
[Babbitt,] the Court did grant Chevron deference to an agency interpretation of the Endangered Species Act, despite
the fact that the Act could be both civilly and criminally enforced.”).
8In Chevron, the regulation at issue was an EPA “final rule” promulgated after notice and comment.
467 U.S. at 840-41; 46 Fed. Reg. 50766, 50767-68 (Oct. 14, 1981). O’Hagan also involved a “final rule,”
promulgated by the SEC after a notice-and-comment period. 521 U.S. at 668; 45 Fed. Reg. 60410, 60410-11 (Sep.
12, 1980)). The same goes for the rule in Babbitt. 515 U.S. at 691 n.2; 40 Fed. Reg. 44412, 44413 (Sep. 26, 1975);
46 Fed. Reg. 54748, 54748 (Nov. 4, 1981).
9See id. at 368-69 (quoting portion of DOJ’s U.S. Attorneys’ Manual stating, “‘The Manual provides only
internal Department of Justice guidance. It is not intended to, does not, and may not be relied upon to create any
rights, substantive or procedural, enforceable at law . . . .’” (citation omitted)); id. at 369 (quoting preface to Air
Force internal guidance—opinions from the Judge Advocate General—stating that the opinions “‘are good starting
points but should not be cited as precedence [sic] without first verifying the validity of the conclusions by
independent research.’” (alteration in original) (citation omitted)).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 47

entitled to Chevron deference in the first place. See Atrium Med. Ctr., 766 F.3d at 567
(“‘[I]nterpretations contained in policy statements, agency manuals, and enforcement guidelines,
all of which lack the force of law’ and were not promulgated via notice and comment
rulemaking, ‘do not warrant Chevron-style deference.’” (quoting Christensen v. Harris County,
529 U.S. 576, 587 (2000))).

Because the statements in Apel and Abramski “were made outside the context of a
Chevron-eligible interpretation,” Guedes, 920 F.3d at 25, they do not resolve our question.
Rather, Chevron, O’Hagan, and Babbitt control. Those cases demonstrate that when the Court
has considered legislative rules promulgated through notice and comment, it has applied
Chevron even when the rules have criminal implications. See id. (noting that in Babbitt, “[w]hen
directly faced with the question of Chevron’s applicability to an agency’s interpretation of a
statute with criminal applications through a full-dress regulation, the Court adhered to Chevron.”
(citation omitted)); Aposhian, 958 F.3d at 984 (“Babbitt . . . govern[s] here, where ATF has
promulgated a regulation through formal notice-and-comment proceedings.”).

The majority recognizes that in O’Hagan and Babbitt, the Supreme Court applied
deference to regulations with criminal applications, Majority Op. at 12-14, but insists that neither
case applied Chevron deference. As noted above, that is mistaken. See supra at 44-46 nn.6-7.10
The majority also cites three pre-2014 cases that, it suggests, “indicated that the rule of lenity—
the practical opposite of Chevron deference—applies to ambiguous statutory provisions that

10Although it never fully articulates the point, the majority also appears to suggest that O’Hagan
and Babbitt relied on a purported “clear-statement” rule—rather than Chevron—to apply deference. Majority Op. at
12-14. It is clear that neither Babbitt nor O’Hagan relied on any clear-statement rule to apply deference. Neither
opinion ever mentions a “clear-statement rule,” and nothing in either opinion suggests that the decision to apply
deference was based on any such rule. The majority cites nothing to support its assertion that Babbitt “appears to
have been relying on the clear-statement rule’s delegation of authority to the DOI as if the DOI were Congress
itself.” Id. at 12-13. As to O’Hagan, the majority cites a footnote from the opinion that says nothing about relying
on a “clear-statement rule.” Id. at 13-14 (citing O’Hagan, 521 U.S. at 673 n.19).
Rather, the Babbitt and O’Hagan Courts simply recognized that Congress had delegated legislative
authority to the agencies in question. Delegation is a necessary prerequisite to Chevron deference, but it is not a
sufficient condition for deference. Otherwise, an agency could issue any regulation—even one completely contrary
to the statute—so long as Congress clearly delegated authority to that agency. That, of course, is not the law, and
nothing about O’Hagan or Babbitt suggests that the Court viewed proper delegation as sufficient on its own to
trigger deference.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 48

have both civil and criminal applications.” Majority Op. at 14. However, none of those cases
says that the rule of lenity trumps Chevron—a position that Babbitt expressly rejected.

For example, the majority cites United States v. Thompson/Center Arms Co., 504 U.S.
505, 517-18 nn.9-10 (1992), which applied the rule of lenity to an ambiguous provision of the
National Firearms Act. But in Thompson/Center there was no agency regulation that addressed
the statutory “question presented” in the case—a point the opinion explicitly noted, id. at 518
n.9—so the Court never had to choose between Chevron and the rule of lenity. Indeed, Babbitt
later distinguished Thompson/Center Arms on that very basis:

We have applied the rule of lenity in a case raising a narrow question concerning
the application of a statute that contains criminal sanctions to a specific factual
dispute—whether pistols with short barrels and attachable shoulder stocks are
short-barreled rifles—where no regulation was present. See United States v.
Thompson/Center Arms Co., 504 U.S. 505, 517-18, and n.9 (1992). We have
never suggested that the rule of lenity should provide the standard for reviewing
facial challenges to administrative regulations whenever the governing statute
authorizes criminal enforcement.

515 U.S. at 704 n.18 (emphasis added). Babbitt’s discussion of Thompson/Center Arms makes
clear that cases discussing the rule of lenity where no regulation is present are of little relevance
here, and that when a case does involve a legislative regulation, Chevron applies.11

11See also Guedes, 920 F.3d at 26 (“Babbitt later made clear that the Court in Thompson/Center had no
occasion to apply Chevron[.]. . . Babbitt implies that Chevron should apply in a case—like this one—involving an
interpretation of the National Firearms Act where a regulation is present.”); Aposhian, 958 F.3d at 983 (Babbitt’s
discussion of Thompson/Center suggests that “where a regulation is at issue, . . . Chevron, not the rule of lenity,
should apply.”).
The other two pre-2014 cases the majority cites are also inapposite. The first, Leocal, never mentions
Chevron, did not involve a regulation, and only discussed the rule of lenity in dictum. Leocal v. Ashcroft, 543 U.S.
1, 11 n.8 (2004); see also Esquivel-Quintana v. Lynch, 810 F.3d 1019, 1024 (6th Cir. 2016) (noting that Leocal’s
discussion of the rule of lenity was dictum and declining to follow it in light of Babbitt’s holding), rev’d on other
grounds sub nom. Esquivel-Quintana v. Sessions, 137 S. Ct. 1562 (2017). The second, SWANCC v. U.S. Army
Corps of Eng’rs, is also inapposite. It declined to apply Chevron on an unrelated basis: there, the agency’s
interpretation of its own jurisdiction under the Clean Water Act would have potentially extended beyond the outer
bounds of Congress’s Commerce Clause authority and would have created federalism concerns. 531 U.S. 159, 173-
74 (2001). The opinion’s only reference to the rule of lenity comes when the Court expressly declines to consider
the argument that the rule of lenity displaces Chevron. See id. at 174 n.8 (“Because violations of the [Clean Water
Act] carry criminal penalties, petitioner invokes the rule of lenity as another basis for rejecting the [agency’s]
interpretation of the CWA. We need not address this alternative argument.” (citations omitted)).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 49

On its way to distinguishing Chevron, O’Hagan, and Babbitt, the majority suggests that
Apel and Abramski “unequivocal[ly]” establish that the Court has never applied deference to an
agency’s interpretation in the criminal context.12 Majority Op. at 11. But as discussed, Apel and
Abramski do not resolve the issue because neither involved Chevron-triggering regulations; and
without such regulations, no deference is warranted. Further, because neither decision even
mentioned Chevron—or Babbitt or O’Hagan—they should not be read to overrule the Court’s
holdings in those cases.

The same is true of the other Supreme Court cases the majority cites. Aside from
SWANCC—which did not discuss the issue presented here other than in declining to address it—
none of the cited cases mentions Chevron, O’Hagan, or Babbitt. At most, their statements, like
those in Apel and Abramski, create an implied tension with Chevron, Babbitt, and O’Hagan. In
essence, the majority—and Plaintiffs—seem to argue that this tension allows us to disregard the
earlier binding authority.13

But it is the Supreme Court’s prerogative, not ours, to deem one of its decisions overruled
by implication. See Rodriguez de Quijas v. Shearson/Am. Exp., Inc., 490 U.S. 477, 484 (1989)
(“If a precedent of this Court has direct application in a case, yet appears to rest on reasons
rejected in some other line of decisions, the Court of Appeals should follow the case which
directly controls, leaving to this Court the prerogative of overruling its own decisions.”);
Agostini v. Felton, 521 U.S. 203, 237-38 (1997) (directing lower courts not to “conclude our

12The majority asserts that Apel and Abramski’s “absolute statement means that none of the Court’s prior
cases applied Chevron deference (or any deference)” to an agency’s regulations in the criminal context. Majority
Op. at 11. But right after making that assertion, the majority recognizes that the Court has done just that. See id. at
12-14 (recognizing that Babbitt and O’Hagan applied deference to regulations carrying criminal penalties). It is
difficult to reconcile these dissonant statements, unless we assume that Apel and Abramski silently revised the
historical fact that the Court applied deference in Babbitt, O’Hagan, and Chevron. As a subordinate federal court,
we may not make that kind of assumption. See infra at 49-50.
13See Majority Op. at 12-14, 27-28 (recognizing that O’Hagan and Babbitt applied deference in criminal
contexts, but later suggesting that the Supreme Court has “undercut [Babbitt] in subsequent cases”); Appellants’ Br.
at 18 (arguing that the Guedes opinion incorrectly “relies on cases decided in the 1990’s,” while “Apel and Abramski
represent the Supreme Court’s most recent pronouncements in this area that is continually evolving further away
from agency deference and towards exclusive judicial review”). The dissent in Guedes did the same. See 920 F.3d
at 41 (Henderson, J., concurring in part and dissenting in part) (noting that Babbitt is not “the last word on this
topic,” and adding that the Court’s “most recent decisions indicate” that it would not apply Chevron to statutes or
rules with criminal sanctions).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 50

more recent cases have, by implication, overruled an earlier precedent” (citing Rodriguez de
Quijas, 490 U.S. at 484)); Hohn v. United States, 524 U.S. 236, 252-53 (1998) (“Our decisions
remain binding precedent until we see fit to reconsider them, regardless of whether subsequent
cases have raised doubts about their continuing vitality.”). Abramski and Apel “did not purport
to overrule” Babbitt or O’Hagan, and “[i]n situations like this, where an advocate insists . . . new
Supreme Court decision[s] undermine[] . . . previous decision[s], the earlier decision[s] stand[]
until the Court says otherwise.” United States v. Bradley, 969 F.3d 585, 591 (6th Cir. 2020)
(citation omitted).

We hewed to that rule in Esquivel-Quintana, 810 F.3d at 1023-24, the only published
opinion from our Circuit to directly address the apparent tension between these two groups of
cases.14 See id. (noting that, despite an increasingly prominent view (based on statements from
cases like Abramski) that the rule of lenity ought to trump Chevron in the criminal context, “the
Supreme Court has not made it the law,” and “[t]o the contrary, . . has reached the opposite
conclusion” in Babbitt); id. at 1024 (“[W]e do not read dicta in Leocal and subsequent cases as
overruling Babbitt, or requiring that we apply the rule of lenity here . . . . As an ‘inferior’ court,
our job is to adhere faithfully to the Supreme Court’s precedents.”).15

2. The Majority’s Independent Rationales Against Applying Chevron

14The majority correctly notes that Esquivel-Quintana—reversed on other grounds—is no longer binding.
But it “continues to be entitled to (at the very least) persuasive weight.” CIC Servs., LLC v. Internal Revenue Serv.,
936 F.3d 501, 507 (6th Cir. 2019) (Thapar, J., dissenting from denial of rehearing en banc). We routinely cite cases
that have been vacated or reversed on other grounds as persuasive precedent. See, e.g. United States v. Ruffin, 783
F. App’x 478, 483 (6th Cir. 2019); Youngblood v. Dalzell, 925 F.2d 954, 959 n.3 (6th Cir. 1991); Meeks v. Ill. Cent.
Gulf R.R., 738 F.2d 748, 751 (6th. Cir. 1984).
15In Dolfi v. Pontesso, 156 F.3d 696, 700 (6th Cir. 1998), we discussed Chevron’s applicability to criminal
laws in a way that supports the majority’s view. See id. (“Judicial deference under Chevron in the face of statutory
ambiguity is not normally followed in criminal cases. The rule of lenity requires a stricter construction of
‘ambiguity in a criminal statute,’ not deference.” (citations omitted)). But this statement was dictum. Before
making it, we noted that the agency regulations in that case were “as silent on the [legal] issue as the statute itself.”
Id. Because there was no regulation purporting to interpret the statutory ambiguity, Dolfi’s brief discussion of
Chevron was unnecessary to its holding. Dolfi also never mentioned O’Hagan or Babbitt. Perhaps for those
reasons, neither of the two opinions in Esquivel-Quintana mentioned Dolfi, despite the in-depth discussions both
opinions offered on this issue. See Esquivel-Quintana, 810 F.3d at 1023-24; id. at 1027-32 (Sutton, J., concurring in
part and dissenting in part).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 51

Concluding that the question remains open, the majority provides three independent
reasons why Chevron ought not apply in this context. I disagree with its proffered rationales.

a. The “Community Expertise” Rationale

The majority first reasons that because criminal laws involve moral judgments, agency
expertise is irrelevant when laws have criminal penalties. Instead, the majority asserts, the true
“experts” are community members who have learned morality from their faith and families, as
opposed to “bureaucrats” with graduate degrees. Majority Op. at 18-21.16

But there are many areas where agency expertise is relevant to laws with criminal
applications. For example, we have highly technical and complex tax, securities, and
environmental-law regimes (which sometimes carry criminal penalties), where individuals’
morality, faith, or family values do not provide the same expertise as does a technical
background in the area. Cf. Gutierrez-Brizuela v. Lynch, 834 F.3d 1142, 1156 (10th Cir. 2016)
(Gorsuch, J., concurring) (observing that agency interpretations of statutes with both civil and
criminal applications fall within a “category that covers a great many (most?) federal statutes
today”). The majority fails to account for the vast regulatory frameworks created by Congress,
which are replete with highly technical and complex regulations that may carry criminal
punishments.

The dispute here is highly technical: the issue is whether a firearm can only constitute a
“machinegun” if it fires a rapid stream of bullets with a single depression of the trigger, or
whether a firearm can also be a “machinegun” if it is equipped with a device that allows it to fire
a rapid stream of bullets with a single pull of the trigger, despite involving a separate trigger
depression for each bullet fired. That is a question focused on mechanics, not morals.

16See id. at 18-19 (“[W]e understand that the [Supreme] Court would consider bureaucrats at the ATF as
experts in firearms technology. But that technical knowledge is inapposite to the question of what should be
criminally punished and what should not. Criminal statutes reflect the value-laden, moral judgments of the
community as evidenced by their elected representatives’ policy decisions. . . . . Since our country’s founding, it has
been understood that the public is both capable of and necessary to the determination of right from wrong legally
and morally. . . . The training for such policy determinations does not come from a graduate school education or
decades of bureaucratic experience. Rather, one develops the expertise necessary to make moral judgments from
sources of a more humble and local origin: one’s family and upbringing. This learning is further informed by
relationships with friends and neighbors, practicing one’s faith, and participation in civic life.”).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 52

The majority never explains how this issue involves morality, other than noting in the abstract
that criminal laws involve “value-laden, moral judgments.” Majority Op. at 18.

But morality cannot explain why Chevron deference is permissible in civil, but not
criminal, contexts. One could just as easily argue that all laws, criminal or civil, reflect value-
laden moral judgments. See generally Cass R. Sunstein & Adrian Vermeule, The Morality of
Administrative Law, 131 HARV. L. REV. 1924 (2018); cf. Barnes v. Glen Theatre, Inc., 501 U.S.
560, 569 (1991) (“‘The law . . . is constantly based on notions of morality . . . .’” (citation
omitted)); Veazie v. Williams, 49 U.S. 134, 154 (1850) (“‘All laws stand on the best and broadest
basis, which go to enforce moral and social duties.’” (citation omitted)). The majority’s
morality-based reasoning fails to coherently explain why Chevron applies to civil but not
criminal contexts. Extended to its logical conclusion, it simply amounts to an attack on the
validity of Chevron and legislative delegation more broadly. Cf. Gutierrez-Brizuela, 834 F.3d at
1156 (Gorsuch, J., concurring) (“[T]ry as I might, I have a hard time identifying a principled
reason why the same rationale[s] [for declining Chevron in the criminal context do not] also
apply to statutes with purely civil application.”). But Chevron is still the law, and legislative
delegation is a reality.

b. The Separation of Powers Rationale

The majority next argues that delegation in the criminal context violates the separation of
powers. Majority Op. at 24-26. The Supreme Court and our Circuit have held that it does not.

The Supreme Court has recognized Congress’s delegation authority in the criminal
context for over a century. For example, in United States v. Grimaud, 220 U.S. 506 (1911),
Congress delegated to the Secretary of Agriculture the power to promulgate rules—with criminal
penalties—to preserve certain forest reserves. Id. at 507-09. The Secretary issued a rule
prohibiting livestock grazing near these reserves without a permit. Id. at 509. The defendants,
sheep farmers, were indicted for violating this rule. Id. They argued that the rule was
unconstitutional because Congress could not “mak[e] it an offense to violate rules and
regulations made and promulgated by the Secretary of Agriculture,” since doing so would
“delegate its legislative power to an administrative officer.” Id. at 513. The Supreme Court
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 53

rejected the challenge. See id. at 521 (rejecting the argument that the rules were invalid merely
“because the violation thereof is punished as a public offense”).

In the ensuing decades, several Supreme Court decisions recognized that Congress may
delegate legislative authority in the criminal context. See, e.g., J.W. Hampton, Jr. & Co. v.
United States, 276 U.S. 394, 406-07 (1928) (“The field of Congress involves all and many
varieties of legislative action, and Congress has found it necessary to use officers of the
executive branch within defined limits, to secure the exact effect intended by its acts of
legislation, by vesting discretion in such officers to make public regulations interpreting a statute
and directing the details of its execution, even to the extent of providing for penalizing a breach
of such regulations.” (citing Grimaud, 220 U.S. at 518) (other citations omitted)); Yakus v.
United States, 321 U.S. 414, 418, 423-25 (1944) (upholding delegation of authority to agency to
issue price-limit regulations under Emergency Price Control Act even though violating the
regulations carried criminal penalties, and rejecting non-delegation and separation-of-powers
challenges by criminal defendants convicted of violating those regulations); United States v.
Mistretta, 488 U.S. 361, 371-74, 394-96 (1989) (upholding delegation of authority to Sentencing
Commission to define criminal sentencing ranges, rejecting non-delegation and separation-of-
powers challenges by criminal defendant).

In Touby v. United States, 500 U.S. 160, 164-69 (1991), the Court upheld a delegation of
legislative authority to the Attorney General to schedule substances under the Controlled
Substances Act—a determination that carried criminal implications—and rejected arguments that
this delegation violated the non-delegation doctrine or the separation of powers. And in United
States v. Stevenson, 676 F.3d 557, 565 (6th Cir. 2012), we held that the “Attorney General was
properly delegated authority by Congress to enact [a] substantive rule” providing that a federal
sex-offender registration statute—which imposed criminal penalties—applied retroactively to
those convicted of sex crimes prior to the statute’s passage. See id. at 563 n.3 (rejecting
defendants’ argument “that Congress lacked the constitutional authority to delegate this power to
the Attorney General”).

The majority acknowledges some of these decisions, Majority Op. at 22, yet still
concludes that it would violate the separation of powers “[i]f Congress were ‘to hand
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 54

responsibility for defining crimes to relatively unaccountable [public officials]’. . . . Because the
community has the right to determine what moral wrongs should be punished . . . that
responsibility may be entrusted to only the branch most accountable to the people: the
legislature. And it may not be blithely delegated away.” Id. at 25-26 (citations omitted).17
Whatever the merits of that view, it is not in accord with the holdings of the Supreme Court and
our Circuit.

c. The Rule of Lenity and Fair Notice Rationale

Finally, the majority argues that ambiguous statutes with criminal penalties ought to be
subject to the rule of lenity, rather than Chevron. Majority Op. at 26-28. If we were writing on a
blank slate, this argument might carry some weight. But the Supreme Court rejected it in
Babbitt; no case has purported to overrule Babbitt; and as a subordinate court, we must follow
Babbitt.

Further, I disagree with the suggestion that applying Chevron would offend the fair notice
that the rule of lenity promotes. The D.C. Circuit persuasively rejected this argument:

Chevron promotes fair notice about the content of criminal law. It applies only
when, at Congress’s direction, agencies have followed “relatively formal
administrative procedure tending to foster the fairness and deliberation that should
underlie a pronouncement of such force.” Mead, 533 U.S. at 230. Importantly,
such procedures, which generally include formal public notice and publication in
the Federal Register, do not “provide such inadequate notice of potential liability
as to offend the rule of lenity.” Babbitt, 515 U.S. at 704 n.18. . . . [I]f the [ATF’s]
Rule is a valid legislative rule, all are on notice of what is prohibited.

Guedes, 920 F.3d at 28. The notice-and-comment process in this case clearly functioned to
inform the public of the intended prohibition. The ATF received over 186,000 comments
regarding the proposed rule before it went into effect. 83 Fed. Reg. at 66,519. One of the
plaintiffs in this case—Gun Owners of America—submitted a comment challenging this rule

17The majority is not consistent on this point. Compare Majority Op. at 12 (“The Court’s traditional
approach, under the modern nondelegation doctrine, has been to allow Congress to delegate to the executive branch
the responsibility for defining crimes . . . .”) with id. at 26 (“Because the community has the right to determine what
moral wrongs should be punished . . . that responsibility may be entrusted to only the branch most accountable to the
people: the legislature. And it may not be blithely delegated away.”).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 55

before it went into effect on behalf of “more than 1.5 million gun owners.”18 Ample notice was
provided by the notice-and-comment process.

In sum, I would apply Chevron. Chevron itself involved a law with criminal penalties, as
did O’Hagan and Babbitt. The only way to get out from under the weight of these binding
decisions is to suggest that Abramski and Apel silently overruled them. However, only the
Supreme Court may do that. And we certainly may not depart from those binding precedents
based on normative disagreements with them.

II. Applying Chevron

The Chevron framework consists of two steps. First, if the statute is unambiguous—i.e.,
“if ‘Congress has directly spoken to the precise . . . issue’ in the text of the statute”—we apply
the statute’s clear meaning. Hernandez v. Whitaker, 914 F.3d 430, 433 (6th Cir. 2019) (quoting
Chevron, 467 U.S. at 842-43)). If the statute is ambiguous, we ask if the agency’s interpretation
is “‘based on a permissible construction of the statute.’” Id. (quoting Chevron, 467 U.S. at 843).

1. A. The Statute is Ambiguous

A statutory phrase is ambiguous when its terms “admit of two or more reasonable
ordinary usages.” Nat’l Cable & Telecomms. Ass’n v. Brand X Internet Servs., 545 U.S. 967,
989 (2005); see also All. for Cmty. Media v. F.C.C., 529 F.3d 763, 777 (6th Cir. 2008) (noting
that a statutory phrase is ambiguous “when ‘to give th[e] phrase meaning requires a specific
factual scenario that can give rise to two or more different meanings of the phrase.’” (alteration
in original) (quoting Beck v. City of Cleveland, 390 F.3d 912, 920 (6th Cir. 2004))). The
statutory phrase at issue here—the definition of “machinegun,” as applied to bump-stocks—is
capable of two or more meanings.

18See Gun Owners of Am., Comment Letter on the Proposed Rulemaking Entitled “Application of the
Definition of Machinegun to ‘Bump Fire’ Stocks and Other Similar Devices” (received Jan. 12, 2018),
https://www.regulations.gov/document?D=ATF-2018-0001-4434.
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 56

The statute defines “machinegun” as follows:

The term “machinegun” means any weapon which shoots, is designed to shoot, or
can be readily restored to shoot, automatically more than one shot, without
manual reloading, by a single function of the trigger. The term shall also include
the frame or receiver of any such weapon, any part designed and intended solely
and exclusively, or combination of parts designed and intended, for use in
converting a weapon into a machinegun, and any combination of parts from
which a machinegun can be assembled if such parts are in the possession or under
the control of a person.

26 U.S.C. § 5845(b). As the majority observes, there are two key sources of dispute over the
statute’s meaning: first, the phrase “single function of the trigger,” and second, the word
“automatically.” Both are ambiguous.

“Single Function of the Trigger.” I agree that the phrase “single function of the trigger”
is capable of two readings: one favoring the government (the “shooter-focused” reading), the
other favoring Plaintiffs (the “mechanical” reading). The shooter-focused reading corresponds to
a single “pull” of the trigger—i.e., a single human action upon the trigger that initiates a rapid-
fire sequence. Under this reading, a bump-stock-equipped rifle constitutes a machinegun
because a single human action—the initial “pull” of the trigger—initiates a rapid firing sequence.
The mechanical reading takes the phrase “single function of the trigger” to mean “single
depression of the trigger.” Under this view, a bump-stock-equipped rifle is not a machinegun
because each bullet fired is initiated by a separate depression of the trigger, albeit one generated
by the weapon’s recoil. Accord Guedes, 920 F.3d at 29; Majority Op. at 30.

Both readings are plausible. “The word ‘function’ focuses on the ‘mode of action’ . . . by
which the trigger operates. But that definition begs the question of whether ‘function’ requires
our focus upon the movement of the trigger, or the movement of the trigger finger. The statute is
silent in this regard.” Aposhian, 958 F.3d at 986 (quoting 4 OXFORD ENGLISH DICTIONARY 602
(1933)).19 See also Majority Op. at 31-32 (looking to contemporaneous dictionaries from around

19See also Guedes, 920 F.3d at 29 (“A mechanical perspective, for instance, might focus on the trigger’s
release of the hammer, which causes the release of a round. From that perspective, a ‘single function of the trigger’
yields a single round of fire when a bump-stock device moves the trigger back and forth. By contrast, from the
perspective of the shooter’s action, the function of pulling the trigger a single time . . . yields multiple rounds of
fire. . . . Neither of those interpretations is compelled (or foreclosed) by the term ‘function’ in ‘single function of the
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 57

1968—when the Gun Control Act of 1968 was passed—and finding that the “dictionary
definition of ‘function’ lends support to both interpretations. . . . [B]ecause ‘function’ means
‘action,’ dictionaries alone do not reveal whether the statute is referring to the mechanical ‘act’
of the trigger’s being depressed or the physical ‘act’ of the shooter’s pulling the trigger.” (citing
WEBSTER’S THIRD NEW INTERNATIONAL DICTIONARY 920-21 (1967); WEBSTER’S SEVENTH NEW
COLLEGIATE DICTIONARY 338 (1967))).

Because the statutory text is ambiguous, “the statute contains a ‘gap for the agency to
fill.’” Guedes, 920 F.3d at 29 (quoting Chevron, 467 U.S. at 843)). The majority reasons that
§ 5845(b)’s statutory context shows that the mechanical reading is the better interpretation,
emphasizing its focus on the word “trigger,” overall focus on the gun’s design and parts, and lack
of comparable reference to the shooter. Majority Op. at 32-33. But “[a]t Chevron’s first step,
we do not ask which . . . interpretation[] is the better reading of the statute. Rather, we ask
whether either of those interpretations is unambiguously ‘compel[led]’ by the statute, to the
exclusion of the other one.” Guedes, 920 F.3d at 30 (alteration in original) (quoting Chevron,
467 U.S. at 860). Here, “the answer is no.” Id.

“Automatically.” The word “automatically” is also ambiguous. The statute provides that
a machinegun is a “weapon which shoots . . . automatically more than one shot, without manual
reloading, by a single function of the trigger.” 26 U.S.C. § 5845(b) (emphasis added). Here, too,
there are competing interpretations, and the text does not unambiguously foreclose either of
them.

Plaintiffs argue that the phrase “automatically” must mean “‘by itself with little or no
direct human control.’” Appellants’ Br. at 24 (citation omitted). They reason that since a
shooter must exert constant pressure to cause a bump-stock-equipped rifle to continue firing,
these devices do not create a weapon that “shoots automatically.” Id. 23-25. The government
responds that “automatically” means “self-acting or self-regulating.” Appellees’ Br. at 28. In
the government’s view, a bump-stock-equipped rifle is “self-acting” in the sense that once the
shooter establishes the conditions necessary to begin the firing process—pulling the trigger,

trigger.’ The word ‘function’ focuses our attention on the ‘mode of action’ . . . by which the trigger operates. But
the text is silent on the crucial question of which perspective is relevant.” (citations omitted)).
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 58

placing a finger on the extension ledge, and applying “pressure on the barrel-shroud or fore-stock
with the other hand”—the “bump stock . . . [can] repeatedly perform its basic purpose: ‘to
eliminate the need for the shooter to manually capture, harness, or otherwise utilize th[e] [recoil]
energy to fire additional rounds.’” Id. at 28-29 (second and third alterations in original) (quoting
83 Fed. Reg. at 66,532)).

According to dictionary definitions at the time the National Firearms Act was issued, the
word “automatically”—the adverbial form of the word “automatic”—means “[h]aving a
self-acting or self-regulating mechanism that performs a required act at a predetermined point in
an operation[.]” WEBSTER’S NEW INTERNATIONAL DICTIONARY 187 (2d ed. 1934); see also 1
OXFORD ENGLISH DICTIONARY 574 (1933) (defining “Automatic” as “[s]elf-acting under
conditions fixed for it, going of itself”). The focus on a “self-regulating mechanism” cuts against
the suggestion that the word “automatically” requires complete, as opposed to partial,
automation, and lends support to the government’s view. Further, Plaintiffs’ argument that
bump-stock-equipped weapons do not fire “automatically” because they require constant forward
pressure is belied by common usage of the word “automatic.” For example, “an ‘automatic’
sewing machine still ‘requires the user to press a pedal and direct the fabric.’” Guedes, 920 F.3d
at 30 (citation omitted)). And an “automatic” car shifts gears on its own, but only if the driver
maintains enough constant pressure on the gas pedal to reach a speed that triggers a gear shift.

As other courts have recognized, the ultimate question is how much human input is
contemplated by the word “automatically.” That is a question of degree that the statute’s text
does not definitively answer. The D.C. Circuit’s explanation captures this point well:

The term “automatically” does not require that there be no human involvement to
give rise to “more than one shot.” Rather, the term can be read to require only
that there be limited human involvement to bring about more than one shot. See,
e.g., Webster’s New International Dictionary 157 (defining “automatically” as the
adverbial form of “automatic”); id. at 156 (defining “automatic” as “self-acting or
self-regulating,” especially applied to “machinery or devices which perform parts
of the work formerly or usually done by hand” (emphasis added)). But how much
human input in the “self-acting or self-regulating” mechanism is too much?
. . . . [T]he phrase “by a single function of the trigger” . . . can naturally be read to
establish only the preconditions for setting off the “automatic” mechanism,
without foreclosing some further degree of manual input such as the constant
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 59

forward pressure needed to engage the bump stock in the first instance. And if so,
then the identified ambiguity endures. How much further input is permitted in the
mechanism set in motion by the trigger? The statute does not say.

Guedes, 920 F.3d at 30-31. Thus, this term is also ambiguous.

B. The ATF’s Interpretation Is Reasonable

At the second step of the Chevron analysis, we ask whether “the agency’s [reading] is
based on a permissible construction of the statute.” Chevron, 467 U.S. at 843. The ATF’s
interpretation of both phrases—“single function of the trigger” and “automatically”—are
permissible constructions, and they are reasonable.

The ATF’s shooter-focused interpretation of “single function of the trigger” is
reasonable. The ATF has viewed the phrase to mean “single pull of the trigger” since 2006,
when it determined that a spring-coiled bump-stock—the “Akins Accelerator”—was a
“machinegun.” 83 Fed. Reg. at 66,517. In 2009 the Eleventh Circuit held that this reading was
“consonant with the statute and its legislative history.” Akins v. United States, 312 F. App’x 197,
200 (11th Cir. 2009); see also Aposhian, 958 F.3d at 988 (agreeing with Akins that this reading is
permissible); Guedes, 920 F.3d at 31 (same). In 1934, when the National Firearms Act was
enacted, the president of the National Rifle Association testified in a congressional hearing that
the term “machine gun” included any gun “‘capable of firing more than one shot by a single pull
of the trigger, a single function of the trigger.’” 83 Fed. Reg. at 66,518 (citation omitted). The
House Report accompanying the bill that became the National Firearms Act said that the bill
“‘contains the usual definition of a machine gun as a weapon designed to shoot more than one
shot . . . by a single pull of the trigger.’” Guedes, 920 F.3d at 31 (quoting H.R. Rep. No.
73-1780, at 2 (1934)). Further, the ATF’s focus on the human factor is reasonable. The practical
effect of the bump-stock device is to turn a semi-automatic firearm into a rapid-fire firearm that
only requires the person firing the gun to pull the trigger once.

The ATF’s interpretation of “automatically” is also reasonable. It allows for some human
involvement, but that “accords with the everyday understanding of the word ‘automatic.’” Id.
The interpretation also fits within some of the relevant dictionary definitions that existed at the
time the National Firearms Act was enacted in 1934—first defining “machinegun”—and when
 No. 19-1298 Gun Owners of Am., Inc., et al. v. Garland, et al. Page 60

the Gun Control Act of 1968 slightly altered that definition.10 In 1934, Webster’s New
International Dictionary defined “automatic” as “[h]aving a self-acting or self-regulating
mechanism.” WEBSTER’S NEW INTERNATIONAL DICTIONARY 187 (2d ed. 1934) (emphasis
added). Dictionaries from 1965 and 1967 do the same. See WEBSTER’S THIRD NEW
INTERNATIONAL DICTIONARY 148 (1965); WEBSTER’S SEVENTH NEW COLLEGIATE DICTIONARY
60 (1967). It is reasonable to read the phrase “automatically” as requiring only a partial self-
regulation—i.e., a mechanism that allows for an integral part of a process to be performed
autonomously.
***
In sum, Chevron deference applies to the ATF’s legislative regulation, the statute is
ambiguous, and the ATF’s construction is reasonable and warrants deference. I therefore
respectfully dissent.

10The 1968 definition dropped the word “semiautomatically” from the 1934 definition and added
references to various parts that, together, could convert a firearm into a machinegun. See Majority Op. at 4.