Aposhian v. Wilkinson

FILED
United States Court of Appeals
PUBLISH Tenth Circuit

UNITED STATES COURT OF APPEALS March 5, 2021

Christopher M. Wolpert
FOR THE TENTH CIRCUIT Clerk of Court
_________________________________

W. CLARK APOSHIAN,

Plaintiff - Appellant,
No. 19-4036
v. (D.C. No. 2:19-CV-00037-JNP-BCW)
(D. Utah)
ROBERT M. WILKINSON, Acting
Attorney General of the United States;
UNITED STATES DEPARTMENT OF
JUSTICE; REGINA LOMBARDO,
Acting Director Bureau of Alcohol
Tobacco Firearms and Explosives;
BUREAU OF ALCOHOL TOBACCO
FIREARMS AND EXPLOSIVES,

Defendants - Appellees.*
------------------------------
CATO INSTITUTE AND FIREARMS
POLICY COALITION; DUE PROCESS
INSTITUTE,

Amicus Curiae.
_________________________________

ORDER
_________________________________

*
Pursuant to Fed. R. App. P 43(c)(2), William Barr is replaced by Robert M.
Wilkinson as Acting United States Attorney General, and Thomas E. Brandon is replaced
by Regina Lombardo as Acting Director of the Bureau of Alcohol Tobacco Firearms and
Explosives.
Before TYMKOVICH, Chief Judge, BRISCOE, LUCERO**, HARTZ, HOLMES,
MATHESON, BACHARACH, PHILLIPS, MORITZ, EID, and CARSON, Circuit
Judges.***

On September 4, 2020, this court entered an order granting Appellant’s Petition

for Rehearing En Banc. Having now considered the parties’ supplemental briefs and

heard oral argument in this matter, a majority of the en banc panel has voted to vacate the

September 4, 2020 order as improvidently granted. As a result, the court’s September 4,

2020 order granting en banc rehearing is VACATED, the court’s May 7, 2020 opinion is

REINSTATED, and the Clerk shall reissue this court’s judgment as of the date of this

order.

Chief Judge Tymkovich, as well as Judges Hartz, Holmes, Eid and Carson would

proceed with en banc rehearing. Chief Judge Tymkovich, Judge Hartz, Judge Eid, and

Judge Carson have written separate dissents from this order, and each has joined in the

others’ dissents. Judge Holmes has also joined all dissents.

All pending motions for leave to file amicus briefs on rehearing are DENIED.

Entered for the Court,

CHRISTOPHER M. WOLPERT, Clerk

**
The Honorable Carlos F. Lucero participated in the en banc court’s
consideration of this matter while still in active status. He took senior status effective
February 1, 2021, but has participated fully in this order.
***
The Honorable Carolyn B. McHugh is recused in this matter.
2
19-4036, Aposhian v. Wilkinson, et al.

TYMKOVICH, Chief Judge, joined by HARTZ, HOLMES, EID, and
CARSON, Circuit Judges, dissenting.

I dissent from the majority’s decision to vacate the en banc order as

improvidently granted. The issues that initially led this court to grant en banc

rehearing remain unresolved and it is important that they be addressed to give

guidance to future panels and litigants. I write separately to identify why the

panel majority wrongly decided the case in the first place and why its opinion will

have deleterious effects going forward.

W. Clark Aposhian brought a pre-enforcement challenge to a rule

promulgated by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF)

that classifies bump stocks as machine guns 1 under the National Firearms Act

(NFA), 26 U.S.C. §§ 5801–5872. The Final Rule was promulgated to clarify the

definition of “machinegun” found in 26 U.S.C. § 5845(b). See 27 C.F.R.

§ 479.11. The Final Rule required owners of bump stocks to destroy them or

abandon them to the ATF by March 26, 2019. See Bump-Stock-Type Devices, 83

Fed. Reg. 66,514, 66,514 (Dec. 26, 2018) (Final Rule).

Mr. Aposhian sought a preliminary injunction from the district court to

prevent ATF from enforcing the Final Rule. The district court denied the motion

for a preliminary injunction, concluding Mr. Aposhian had not shown a likelihood

1
I use the two-word spelling of machine gun except when quoting sources.
of success on the merits of his challenge. Mr. Aposhian then filed an

interlocutory appeal with this court.

The panel majority who considered the interlocutory appeal affirmed the

district court. See Aposhian v. Barr, 958 F.3d 969 (10th Cir. 2020). The panel

agreed with the district court that Mr. Aposhian had not demonstrated a likelihood

of succeeding on the merits of his claim. 2 But it departed from the district court’s

reasoning. While the district court had concluded the best reading of

“machinegun” in § 5845(b) included bump stocks, the panel majority found the

statute ambiguous. Id. at 985–88. Having identified an “ambiguity,” the panel

applied Chevron deference to the ATF’s interpretation of § 5845(b). Id. at 988.

Given this deference, Mr. Aposhian had no realistic path to success. The panel

found ATF’s application of § 5845(b) to bump stocks to be a permissible reading

of the statute and denied Mr. Aposhian’s request for a preliminary injunction.

I believe the panel majority went looking for ambiguity where there was

none. Then, having found ambiguity, it unnecessarily placed a thumb on the scale

for the government by invoking Chevron deference. The panel majority did this

2
To prevail on a motion for a preliminary injunction, the movant must
show “(1) a substantial likelihood of success on the merits; (2) irreparable harm
to the movant if the injunction is denied; (3) the threatened injury outweighs the
harms that the preliminary injunction may cause the opposing party; and (4) the
injunction, if issued, will not adversely affect the public interest.” Gen. Motors
Corp. v. Urban Gorilla, LLC, 500 F.3d 1222, 1226 (10th Cir. 2007).

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even though ATF maintained the statute was unambiguous and did not claim its

interpretation was entitled to any special deference. The panel also applied

Chevron even though ATF’s Final Rule has criminal, as well as civil,

consequences. In doing so, the panel majority further confused this court’s law

about whether Chevron can be waived and whether the rule of lenity can ever be

used to resolve ambiguities when Chevron might also apply to statutes with

criminal penalties. Now, by vacating the en banc order as improvidently granted,

the court deprives us of the chance for much-needed clarity on these issues.

I. Likelihood of Success on the Merits

As an initial matter, Mr. Aposhian has shown a likelihood of success on the

merits. Section 5845(b) unambiguously excludes bump stocks from its ambit.

And even if the statute is ambiguous, Chevron deference is inapplicable here for

several reasons. First, the government consistently refused to invoke Chevron

deference for its interpretation. That is a decision we should respect. And

second, because the Final Rule interprets a statute with criminal consequences, we

must resolve ambiguity through the rule of lenity before ever reaching for

Chevron. The manner in which the panel majority addressed these issues is not

only wrong, it creates an unfortunate amount of uncertainty for future litigants.

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 A. Standard of Review

The standard for reviewing a district court’s denial of a preliminary

injunction is abuse of discretion. Fish v. Kobach, 840 F.3d 710, 723 (2016). The

district court abuses its discretion when its decision is premised “on an erroneous

conclusion of law or where there is no rational basis in the evidence for the

ruling.” Id. (internal quotation marks omitted). We evaluate the district court’s

legal determinations de novo. Id.

B. Statutory Framework

I am not the first to spill ink over this issue, so I will keep my description

of the statutory regime brief. See Aposhian, 958 F.3d 969; see also Guedes v.

Bureau of Alcohol, Tobacco, Firearms and Explosives, 920 F.3d 1 (D.C. Cir.

2019), cert. denied, 140 S. Ct. 789 (2020). The NFA, originally passed in 1934,

“imposes strict registration requirements on statutorily defined ‘firearms.’”

Staples v. United States, 511 U.S. 600, 602 (1994). Machine guns are among

those firearms subject to regulation and registration under the NFA. See 26

U.S.C. § 5845(a). Under § 5845(b), a “machinegun” is “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 statutory definition also includes “any part designed and intended

. . . for use in converting a weapon into a machinegun.” Id.

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 The Gun Control Act of 1968 (GCA), as amended by the Firearm Owners’

Protection Act of 1986, Pub. L. No. 99-308, 100 Stat. 449, incorporated the

NFA’s definition of machine gun. 18 U.S.C. § 921(a)(23). These acts went

beyond mere regulation, criminalizing almost all possession of machine guns. See

id. at § 922(o)(1).

No such blanket prohibition exists for possession of semiautomatic rifles,

which require separate pulls of the trigger for each bullet fired. As a result,

firearm manufacturers have created accessories that allow a semiautomatic rifle to

increase the speed with which it can fire a single round. A bump stock is one

such accessory. It is intended to replace the rifle’s standard stock, the part of the

rifle that usually rests against the shooter’s shoulder. This frees “the weapon to

slide back and forth rapidly, harnessing the energy from the firearm’s recoil either

through a mechanism like an internal spring or in conjunction with the shooter’s

maintenance of pressure.” Bump-Stock-Type Devices, 83 Fed. Reg. at 66,516.

For a non-mechanical bump stock—one without an internal spring—to work as

intended, the shooter must maintain backward pressure with his trigger finger and

forward pressure on the rifle’s barrel with his non-trigger hand. The channeled

recoil from the bump stock then causes the trigger to reset and bump repeatedly

against the shooter’s stationary trigger finger, resulting in a rate of fire

comparable to a machine gun.

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 ATF classified a bump stock device as a “machinegun” for the first time in

2006. Specifically, “ATF concluded that a device attached to a semiautomatic

firearm that uses an internal spring to harness the force of a firearm’s recoil so

that the firearm shoots more than one shot with a single pull of the trigger is a

machinegun.” Id. at 66,514. But over the next decade, ATF issued classification

decisions in which it repeatedly assured bump stock owners that non-mechanical

bump stocks were not machine guns as understood in § 5845(b). Id.

In 2017, a shooter used a non-mechanical bump stock to attack a large

crowd attending an outdoor concert in Las Vegas. Scores died and hundreds were

injured during this senseless act of violence. Following this tragic incident,

members of Congress and the President asked ATF to examine these past

classifications. Id. at 66,516. ATF reviewed its definition and then went through

the formal notice-and-comment process to update its understanding of what

qualifies as a machine gun. Id. at 66,517. The Final Rule clarified the definition

of “machinegun” in § 5845(b), stating

[f]or purposes of this definition, the term
“automatically” as it modifies “shoots, or can be readily
restored to shoot,” means functioning as the result of a
self-acting or self-regulating mechanism that allows the
firing of multiple rounds through a single function of the
trigger; and “single function of the trigger” means a
single pull of the trigger or analogous motions. The
term “machine gun” includes a bump-stock-type-device,
i.e., a device that allows a semi-automatic firearm to
shoot more than one round with a single pull of the

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 trigger by harnessing the recoil energy of the semi-
automatic firearm to which it is affixed so that the
trigger resets and continues firing without additional
manipulation of the trigger by the shooter.

27 C.F.R. § 479.11.

The Final Rule was set to take effect on March 26, 2019, at which point

everyone who possessed a bump stock was supposed to destroy it or turn it over to

ATF. Bump-Stock-Type Devices, 83 Fed. Reg. at 66,514.

C. The Statute Is Unambiguous

Mr. Aposhian argued before the district court and the panel that ATF

exceeded its authority by including bump stocks within the definition of

“machinegun” in its Final Rule. Under the Administrative Procedure Act (APA),

courts must “hold unlawful and set aside agency action, findings, and conclusions

found to be . . . in excess of statutory jurisdiction, authority, or limitations, or

short of statutory right.” 5 U.S.C. § 706(2)(C).

When evaluating an agency’s interpretation of a statute, we often afford its

interpretation Chevron deference. Chevron requires courts to defer to an agency’s

interpretation of a statute “even if the agency’s reading differs from what the

court believes is the best statutory interpretation.” Nat. Cable & Telecomms.

Ass’n v. Brand X Internet Servs., 545 U.S. 967, 980 (2005). But such deference is

not automatically warranted whenever an agency issues a statement regarding its

understanding of a statute. Courts apply Chevron deference only “[i]f a statute is

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ambiguous, and if the implementing agency’s construction is reasonable.” Id.

Here, § 5845(b) contains no ambiguity so “Chevron leaves the stage.” Epic Sys.

Corp. v. Lewis, 138 S. Ct. 1612, 1630 (2018).

As a reminder, § 5845(b) defines a “machinegun” as “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 question before the panel was whether this definition includes non-

mechanical bump stocks. The panel majority regarded two parts of the statutory

definition as sufficiently ambiguous for Chevron deference to apply: “single

function of the trigger” and “automatically.”

Chevron deference “is not due unless a court, employing traditional tools of

statutory construction, is left with an unresolved ambiguity.” Epic Sys. Corp.,

138 S. Ct. at 1630. Among other tools, this includes “examination of the statute’s

text, structure, purpose, history, and relationship to other statutes” with an

emphasis on a word or phrase’s “plain meaning.” Harbert v. Healthcare Servs.

Grp., Inc., 391 F.3d 1140, 1147, 1149 (10th Cir. 2004). The fact that self-

interested litigants disagree as to the meaning of a statute does not render it

ambiguous. See In re Woolsey, 696 F.3d 1266, 1273 (10th Cir. 2012) (explaining

that this is “an ailment surely afflicting most every statutory interpretation

question in our adversarial legal system”).

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 The panel majority, however, evaded these rules of interpretation. Rather

than attempt to resolve ambiguity, the panel majority performed interpretive

gymnastics to create ambiguity. In truth, neither of the parties really dispute the

meaning of any words or phrases in the statutory definition of “machinegun.”

They dispute only whether the meaning encompasses bump stocks. And the

answer to that question is apparent on the face of the statute.

A “single function of the trigger” is not ambiguous. At the time the NFA

was passed, a “function” meant the “action” of the trigger. Webster’s New

International Dictionary 1019 (2d ed. 1934). The use of the word “function”

continues to capture the different ways that triggers can work. As the government

explained in the Final Rule, triggers can initiate fire “by voice command,

electronic switch, swipe on a touchscreen or pad, or any conceivable number of

interfaces.” Bump-Stock-Devices, 83 Fed. Reg. at 66,534. Whether a trigger is

pushed, pulled, switched, or swiped, each involves a “single function.”

The panel majority insists this language is ambiguous because “a single

function of the trigger” can be interpreted to refer to the trigger or the shooter.

See Aposhian, 958 F.3d at 986 (arguing the statutory language “begs the question

of whether ‘function’ requires our focus upon the movement of the trigger, or the

movement of the trigger finger”). But the panel majority finds ambiguity where

there is none. The statute’s plain language makes clear the “function” must be “of

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the trigger.” 26 U.S.C. § 5845(b) (emphasis added). The statute speaks only to

how the trigger acts, making no mention of the shooter. 3

The statute’s plain meaning unambiguously excludes bump stocks. A

semiautomatic rifle, equipped with a bump stock, does not fire multiple shots by a

single function of the trigger. “The trigger on that type of rifle must necessarily

‘pull’ backwards and release the rifle’s hammer . . . every time that the rifle

discharges . . . . The rifle cannot fire a second round until both the trigger and

hammer reset.” Aposhian, 958 F.3d at 995 (Carson, J., dissenting). Every shot

requires the trigger to go through this full process again. The fact that a bump

stock accelerates this process does not change the underlying fact that it requires

multiple functions of the trigger to mimic a machine gun.

Likewise, “automatically” is not so ambiguous as to imply Congress

intended ATF to engage in gap-filling. In fact, ATF disclaims any gap-filling in

the Final Rule. See Bump-Stock-Type Devices, 83 Fed. Reg. at 66,519. Far from

indicating any statutory ambiguity, ATF’s proposed definition in the Final Rule

“accords with the everyday understanding of the word ‘automatic[ally].’”

3
And the same is true of ATF’s definition. See Guedes, 920 F.3d at 43
(Henderson, J., dissenting) (“The Rule’s definition describes the ‘motion’ of the
trigger, not of the trigger finger . . . . Indeed, nothing in the Rule’s definition
refers to a shooter’s finger or a volitional action.”). To consider the shooter or
the trigger-finger in the statute or ATF’s definition is to read in language that
simply is not there.

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Guedes, 920 F.3d at 31. It defines “automatically” as “having a self-acting or

self-regulating mechanism that performs a required act at a predetermined point in

the operation.” Bump-Stock-Type Devices, 83 Fed. Reg. at 66,519 (quoting

Webster’s New International Dictionary 187 (2d ed. 1934)). Mr. Aposhian does

not contest this definition. Rather, he contests its application to bump stocks.

The panel majority unnecessarily abstracts “automatically” from the rest of

the statutory language to render the word ambiguous. The statute says a machine

gun is designed to shoot “automatically more than one shot, without manual

reloading, by a single function of the trigger.” 26 U.S.C. § 5845(b) (emphasis

added). “Section 5845(b)’s awkward syntax does not equal ambiguity.” Guedes,

920 F.3d at 183 (Henderson, J., dissenting). The statute is unambiguous about

what makes the firearm shoot automatically: the function of the trigger. To track

with the dictionary definition, the statute itself identifies the “predetermined point

in the operation” at which the “self-regulating mechanism performs the required

act.” If a single function of the trigger and then some other input is required to

make the firearm shoot automatically, we are not talking about a “machinegun” as

defined in § 5845(b).

The government conceded during the en banc oral argument that if a

shooter pulls the trigger of a semiautomatic rifle equipped with a non-mechanical

bump stock without doing anything else, the rifle will fire just one shot. Oral

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Arg. at 1:01:40, Aposhian v. Rosen (2021) (19-4036). That’s why the statute is

unambiguous. To make the firearm “shoot automatically more than one shot”, the

shooter must also be pulling forward on the barrel of the gun. Because a bump

stock requires this extra physical input, it does not fall within the statutory

requirement that the weapon shoot “automatically . . . by a single function of the

trigger.” 26 U.S.C. § 5845(b).

D. Chevron Does Not Apply Here

1. The Government Waived Chevron

Throughout litigation, the government has maintained that the Final Rule

represents the best reading of § 5845(b). It has consistently refused to invoke

Chevron deference. The panel majority paid no heed to this steadfast refusal.

Instead, the panel majority scoured the briefs to justify bringing an uninvited

guest to the statutory interpretation party.

According to the majority, all the court needs is an “invitation” to apply

Chevron deference. Aposhian, 958 F.3d at 981–82. And that invitation can be

brought by either party—it need not be brought by the government, whom

Chevron benefits. In fact, even a brief argument in a footnote opposing the

application of Chevron deference constitutes such an invitation. Id. (citing

TransAm Trucking, Inc. v. Admin. Review Bd., 833 F.3d 1206, 1212 n.4 (10th Cir.

2016)).

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 This theory of waiver is untenable. Under the panel majority’s theory, a

party that challenges an agency’s interpretation of a rule is forced to dance around

Chevron, even where the government has not invoked it. Chevron becomes the

Lord Voldemort of administrative law, “the-case-which-must-not-be-named.” And

litigants bold enough to expressly oppose Chevron in their briefing will be left

guessing whether their reference to the case was fleeting or perfunctory enough to

avoid making an invitation. All the while, courts are given a troubling amount of

freedom when deciding whether to use Chevron—discretion that will dictate the

outcome in many cases.

Even the panel majority acknowledged it was unsure whether its invitation

theory is correct. See id. at 982 n.6. And yet the en banc majority is perfectly

content to leave this confusion in place. This failure to clarify our rule about

whether Chevron can be waived has real implications for litigants and courts in

our circuit. Plaintiffs challenging an agency’s interpretation of a statute are left

guessing how to approach a given case. Should they argue vigorously against

Chevron in their briefing? Should they go to lengths to avoid mentioning

Chevron and its progeny at all? Or are all such litigation decisions futile because

a court can sua sponte apply Chevron whenever it pleases? The majority’s

decision to vacate the en banc order leaves us all without a clear answer.

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 For my part, I believe we must abide by the government’s decision to forgo

Chevron deference. I come to this conclusion for two reasons.

First, the normal rules that govern party presentation and waiver should

apply to Chevron. “[W]hen a party chooses not to pursue a legal theory

potentially available to it, we generally take the view that it is ‘inappropriate’ to

pursue that theory in our opinions.” Hydro Res., Inc. v. EPA, 608 F.3d 1131,

1146 n.10 (10th Cir. 2010) (en banc). We refuse to consider arguments a party

fails to make because we depend “on the adversarial process to test the issues for

our decision” and are concerned “for the affected parties to whom we traditionally

extend notice and an opportunity to be heard on issues that affect them.” Id. 4

4
To be sure, courts treat some issues as non-waivable. For instance,
parties typically cannot waive the proper standard of review. See, e.g., United
States v. Fonseca, 744 F.3d 675, 682 (10th Cir. 2014) (“[T]he court, not the
parties, must determine the standard of review, and therefore, it cannot be
waived.”) (internal quotation marks omitted). Likewise, we are not bound by a
party’s failure to make an argument regarding statutory interpretation. See Kamen
v. Kemper Financial Servs., Inc., 500 U.S. 90, 99 (1991) (“When an issue or
claim is properly before the court, the court is not limited to the particular legal
theories advanced by the parties, but rather retains the independent power to
identify and apply the proper construction of governing law.”).

But Chevron is neither a standard of review nor a canon of construction.
The APA describes the appropriate standards of review for reviewing agency
actions. See 5 U.S.C. § 706. Chevron is not among them. And unlike the
traditional tools of statutory interpretation, Chevron is not concerned with
ascertaining the fixed meaning of a statute. Once a statute is deemed ambiguous,
a statute interpreted pursuant to Chevron can be understood in any number of
ways that could change as the political winds blow.

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 Courts and parties undoubtedly benefit from this type of adversarial

presentation of Chevron. Chevron’s applicability in a given case is seldom

straightforward. See Gonzalez v. Oregon, 546 U.S. 243, 258 (2006) (“Chevron

deference, however, is not accorded merely because the statute is ambiguous and

an administrative official is involved.”). Rather, whether Chevron applies is

often contested and unclear. Among the issues courts must consider is whether

the agency acted with the requisite formality, see United States v. Mead Corp.,

533 U.S. 218, 229–31 (2001), whether the statute deals with a major question

Congress would not have intended to delegate, see King v. Burwell, 576 U.S. 473,

485–86 (2015), and whether the agency has adopted a specific and consistent

position, see Epic Sys. Corp., 138 S. Ct. at 1630. All this to say: it is often not

apparent at first blush whether Chevron should apply.

In practice, courts have applied the party-presentation rule to Chevron. The

Supreme Court has deemed Chevron to be waived when inadequately invoked.

See, e.g., Est. of Cowart v. Nicklos Drilling Co., 505 U.S. 469, 477 (1992)

(concluding that when an agency does not ask for special deference to its

interpretation “we need not resolve the difficult issues regarding deference which

would be lurking in other circumstances”). We have followed the Court’s lead in

our own practice. Hydro Res., 608 F.3d at 1146 (“[W]e need not decide whether

EPA’s interpretation of the statute is entitled to deference because, throughout the

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proceedings before the panel and now the en banc court, EPA itself hasn’t

claimed any entitlement to deference.”); see also Hays Med. Ctr. v. Azar, 956

F.3d 1247, 1264 n.18 (10th Cir. 2020) (same).

Second, when the government does not invoke Chevron as part of its

litigation strategy, the preconditions for Chevron are not present. For Chevron to

apply, two conditions must be met: (1) Congress must delegate authority to the

agency to make rules carrying the force of law and (2) the agency’s ensuing

interpretation must be “promulgated in the exercise of that authority.” Mead, 533

U.S. at 226–27. The agency’s litigation position is no less an exercise of that

authority than the agency’s interpretation. See Guedes v. Bureau of Alcohol,

Tobacco, Firearms, and Explosives, 140 S. Ct. 789, 790 (2020) (Gorsuch, J.,

statement regarding denial of certiorari) (“If the justification for Chevron is that

policy choices should be left to the executive branch officials directly accountable

to the people, then courts must equally respect the Executive’s decision not to

make policy choices in the interpretation of Congress’s handiwork.”) (internal

quotation marks omitted) (emphasis in original).

Here, in promulgating the Final Rule, ATF insisted its definitions

represented “the best interpretation” and accorded “with the plain meaning” of the

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statute. 5 Bump-Stock-Type Devices, 83 Fed. Reg. at 66,521, 66,527. And during

litigation, the government repeatedly disavowed Chevron deference. Aple. Br. at

16 (“[P]laintiff’s discussion of Chevron deference has no bearing on the

disposition of this suit.”); id. at 36 (“[N]othing in the Rule suggest that its legality

depends on the application of Chevron deference, or that the agency believed

Chevron deference was required to uphold the rule.”). ATF does not believe it

promulgated the Final Rule pursuant to Chevron. If the agency disavows any

reliance on Chevron, who are we to second-guess it?

Whether we view the issue as one of waiver or of Chevron’s applicability,

the result is the same. We cannot sua sponte raise Chevron deference. In this

case, that means we must do what courts have done for centuries and interpret the

statute the old-fashioned way: de novo. As indicated above, doing so leads to a

clear result: bump stocks are not machine guns.

2. The Rule of Lenity Resolves Any Ambiguity

Even if Chevron cannot be waived and is applicable here, it cannot and

should not jump the line when courts interpret an ambiguous statute. As a

reminder, Chevron only kicks in once the traditional tools of interpretation have

been exhausted. See Epic Sys. Corp., 138 S. Ct. at 1630. But the panel majority

5
In the Final Rule, ATF invokes Chevron as a last resort, arguing “even if
those terms are ambiguous, this rule rests on a reasonable construction of them.”
Id. at 66,527.

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did not exhaust all the traditional tools. We still have one left in our toolbox: the

rule of lenity. And it “is more than up to the job of solving today’s interpretive

puzzle.” Id.

The rule of lenity is a substantive canon of construction applied in statutory

interpretation cases involving criminal laws. The rule dictates that “when there

are two rational readings of a criminal statute, one harsher than the other, we are

to choose the harsher only when Congress has spoken in clear and definite

language.” McNally v. United States, 483 U.S. 350, 359–60 (1987); see also

United States v. Universal C.I.T. Credit Corp., 344 U.S. 218, 222 (1952) (“We

should not derive criminal outlawry from some ambiguous implication.”). “To

invoke the rule, we must conclude that there is a grievous ambiguity or

uncertainty in the statute.” Muscarello v. United States, 524 U.S. 125, 138

(1998). And the panel majority was correct in identifying it as a “rule of last

resort.” Aposhian, 958 F.3d at 978 n.4.

But it is not clear to me that the level of ambiguity required to invoke the

rule of lenity is any different from that necessary to invoke Chevron. And I am

admittedly lost as to why Chevron gets to cut in front of the rule of lenity in the

statutory interpretation line. Chevron is of recent provenance. It is a rule of

interpretive convenience, rooted in notions of agency expertise and political

accountability. See Chevron, U.S.A., Inc. v. Nat. Res. Defense Council, Inc., 467

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U.S. 837, 865 (1984). The rule of lenity, by contrast, “provides a time-honored

interpretive guideline.” Liparota v. United States, 471 U.S. 419, 427 (1985). It

addresses core constitutional concerns: fair notice and the separation of powers.

United States v. Kozminski, 487 U.S. 931, 952 (1988); see also United States v.

Wiltberger, 5 Wheat. 76, 95 (1820) (Marshall, C.J.) (“It is founded on the

tenderness of the law for the rights of individuals; and on the plain principle that

the power of punishment is vested in the legislative, not the judicial department.

It is the legislature . . . which is to define a crime, and ordain its punishment.”).

Applying Chevron deference to an agency’s interpretation of a statute does not

address either of those concerns.

Take the present case as an example. The definition of “machinegun” in

§ 5845(b) has both civil and criminal consequences. See 18 U.S.C. 922(o)(1)

(making it unlawful to possess a machine gun). The rule of lenity applies to such

statutes. See Leocal v. Ashcroft, 543 U.S. 1, 11 n.8 (2004) (“Because we must

interpret the statute consistently, whether we encounter its application in a

criminal or noncriminal context, the rule of lenity applies.”); see also United

States v. Thompson/Center Arms Co., 504 U.S. 505, 517–18 (1992) (Breyer, J.,

plurality) (“The key to resolving the ambiguity lies in recognizing that although it

is a tax statute we now construe in a civil setting, the NFA has criminal

-19-
consequences . . . . It is proper, therefore, to apply the rule of lenity and resolve

the ambiguity in Thompson/Center’s favor.”).

Section 5845(b) as re-interpreted by ATF does not provide citizens with

fair notice of what conduct is criminalized. When an agency can define criminal

conduct, there is a genuine concern that “if [they] are free to ignore the rule of

lenity, the state could make an act a crime in a remote statement issued by an

administrative agency.” See Carter v. Welles-Bowen Realty, Inc., 736 F.3d 722,

732 (6th Cir. 2013) (Sutton, J., concurring). The government insists fair notice

concerns are not implicated here because the Final Rule is not tucked away in

obscurity. Rather, the Final Rule went through notice and comment and is

published in the Federal Register.

But this is cold comfort to a citizen tasked with conforming their conduct to

the law. The government expects an uncommon level of acuity from average

citizens to know that they must conform their conduct not to the statutory

language, but to the interpretive gap-filling of an agency which may or may not be

upheld by a court. Justice Gorsuch recently expressed this same concern

regarding a case with nearly identical facts:

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

-20-
 “reasonable”; and to guess again whether a later and
opposing agency interpretation will also be held
“reasonable”?

Guedes, 140 S. Ct. at 790 (statement regarding denial of certiorari). When an

agency plays pinball with a statute’s interpretation, as the ATF has here, fair

notice cannot be said to exist.

Furthermore, the Final Rule violates the separation of powers. It is not by

sheer happenstance or convenience that Congress writes the criminal laws.

Rather, “because of the seriousness of criminal penalties, and because criminal

punishment usually represents the moral condemnation of the community,

legislatures and not courts should define criminal activity.” United States v. Bass,

404 U.S. 336, 348 (1971). ATF has no authority to substitute its moral judgment

concerning what conduct is worthy of punishment for that of Congress.

And we should feel deep discomfort at allowing an agency to define the

very criminal rules it will enforce by implicit delegation. Such a delegation

“turn[s] the normal construction of criminal statutes upside down, replacing the

doctrine of lenity with a doctrine of severity.” Carter, 736 F.3d at 730 (Sutton,

-21-
J., concurring). 6 The delegation raises serious constitutional concerns by making

ATF the expositor, executor, and interpreter of criminal laws.

Applying the rule of lenity to § 5845(b) would alleviate these concerns.

The rule of lenity instructs us, when confronted with two possible understandings

of a statute, to adopt the narrower construction. With the rule aiding our

interpretation, § 5845(b) clearly answers the issue at hand: bump stocks do not

fall within the definition of machine gun.

Still, the panel majority says the rule of lenity does not apply here.

In doing so, the panel majority fails to explain why the rule of lenity should

receive such a disfavored status among the rules of construction. We have

regularly applied similar substantive canons of construction before reaching

Chevron. For instance, constitutional avoidance is a canon of construction that

resolves statutory ambiguities to avoid potential constitutional issues. And like

the rule of lenity, “the canon of constitutional avoidance comes into play only

when, after the application of ordinary textual analysis, the statute is found to be

6
Citing United States v. Touby, 500 U.S. 160 (1991), the government
argues that it is well within Congress’s power to give agencies the power to
define crimes. But if Congress wants to give the executive branch discretion to
define criminal conduct, it must speak “distinctly.” United States v. Grimaud,
220 U.S. 506, 519 (1911). Touby involved such an express delegation of
interpretive authority to the attorney general. Here, we are far removed from the
statute at issue in Touby. We are having to infer from ambiguity, not an express
delegation, that Congress implicitly authorized ATF to define criminal conduct.

-22-
susceptible of more than one construction.” Hernandez-Carrera v. Carlson, 547

F.3d 1237, 1245 (10th Cir. 2008). And yet we have said “[i]t is well established

that the canon of constitutional avoidance does constrain an agency’s discretion to

interpret statutory ambiguities, even when Chevron deference would otherwise be

due.” Id. at 1249. We have done the same with other canons of construction.

See, e.g., Ramah Navajo Chapter v. Lujan, 112 F.3d 1455, 1462 (10th Cir. 1997)

(applying the canon of construction favoring Native Americans rather than

Chevron). Why should we favor some substantive canons over Chevron but not

the longstanding rule of lenity?

Faced with these conundrums, the panel majority looks to a footnote in a

Supreme Court opinion to serve as the lodestar for its reasoning. See Babbitt v.

Sweet Home Chapter of Cmtys. for a Greater Ore., 515 U.S. 687, 704 n.18

(1995). In Babbitt, the Court was confronted with an agency’s interpretation of a

statute that had both civil and criminal consequences. The majority applied

Chevron rather than the rule of lenity. In making this prioritization, Justice

Stevens wrote: “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.” Id. And he

went on to say “[e]ven if there exist regulations whose interpretations of statutory

criminal penalties provide such inadequate notice of potential liability as to

-23-
offend the rule of lenity, the ‘harm’ regulation, which has existed for two decades

and gives fair warning of its consequences, cannot be one of them.” Id. The

majority takes this footnote and turns it into a categorical rule: “where a

regulation is at issue, and the agency (here, ATF) has both civil and criminal

enforcement authority, Babbitt suggests that Chevron, not the rule of lenity,

should apply.” Aposhian, 958 F.3d at 983.

The panel majority reads the Babbitt footnote for more than it is worth.

Babbitt does not prevent us from applying the rule of lenity here for several

reasons. First, Justice Steven’s abbreviated reasoning did not create any binding

rule about the relationship between lenity and Chevron in all circumstances. The

footnote is composed of four sentences of reasoning. And it addresses only one

of the concerns underlying the rule of lenity—fair notice—but not the other—the

separation of powers. “[O]ne would have expected the Court to say more before

allowing agencies to trump a doctrine Chief Justice Marshall described as

‘perhaps not much less old than construction itself.’” Carter, 736 F.3d at 735

(Sutton, J., concurring) (quoting Wiltberger, 5 Wheat. at 95).

The post-Babbitt cases further punctuate the limits of the footnote. Several

years after Babbitt, the Court declined to weigh in on the interaction between

Chevron deference and the rule of lenity. See Solid Waste Agency of N. Cook Cty.

v. U.S. Army Corps of Eng’rs, 531 U.S. 159, 174 n.8 (2001). And the Court’s

-24-
most recent decisions have also indicated the government’s interpretation of

criminal laws should not receive deference. See, e.g., 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 courts, not for the Government, to

construe.”). The panel majority acknowledges these statements by the Court, but

insists Chevron deference was not in play in either Apel or Abramski. But the

panel majority gives no reason, other than Babbitt’s allegedly categorical

footnote, as to why we should treat any differently a case in which Chevron would

otherwise be applicable.

Even if some binding rule about the rule of lenity and Chevron exists in

Babbitt, that rule would not apply here. The regulation at issue in Babbitt had

been on the books for twenty years. So, any concerns about fair warning were

significantly diminished. The same cannot be said about ATF’s Final Rule. For

over a decade, ATF consistently reassured the owners of bump stocks that their

property did not fall within the definition of “machinegun.” Then, in just over a

year, it performed an about-face on its own interpretation. The regulation at issue

here does not fall within Babbitt’s purview.

* * *

-25-
 For all these reasons, Mr. Aposhian has demonstrated that his claim is

likely to succeed.

II. Irreparable Harm

Having already determined that Mr. Aposhian was not likely to succeed on

the merits of his claim, the panel majority proceeded to the other prongs of the

preliminary injunction test. But in doing so, it created further confusion.

In its briefing before the district court, the government conceded the second

prong of the preliminary injunction test. The government “acknowledge[d] that

the irreparable harm prong of the preliminary injunction test is met here.” Aplt.

App. 106. And the district court recognized and accepted this concession: “The

parties do not dispute that Mr. Aposhian will experience irreparable harm if the

injunction is denied.” Id. at 131.

Yet, on appeal, the government argued it was not bound by this concession

and the panel majority agreed. Untethered from what happened below, the panel

majority concluded Mr. Aposhian had not shown irreparable harm—yet another

reason to deny his request for a preliminary injunction. The panel cited Dominion

Video Satellite, Inc. v. Echostar Satellite Corp., 356 F.3d 1256 (10th Cir. 2004),

to support its conclusion that a “stipulation without more is insufficient to support

an irreparable harm finding.” Aposhian, 958 F.3d at 990 (quoting Dominion, 356

F.3d at 1266).

-26-
 I am not convinced. Dominion dealt explicitly with a pre-litigation

contractual stipulation, not a formal concession by a party opposing a preliminary

injunction. District courts are entirely capable of managing a preliminary

injunction. And when a district court recognizes a formal concession by a party

which relieves the other party of its burden, we as the appellate court are bound

by that concession. See Christian Legal Soc’y Chapter of the Univ. Of Cal.,

Hastings Coll. of L. v. Martinez, 561 U.S. 661, 677 (2010) (explaining that

“factual stipulations are formal concessions . . . that have the effect of

withdrawing a fact from issue and dispensing wholly with the need for proof of

the fact . . . . [A] judicial admission is conclusive in the case.”) (internal

quotation marks omitted).

It was improper for the panel majority to ignore the government’s

concession regarding irreparable harm. And it puts parties seeking preliminary

injunctions in a bind. Can they no longer rely on an opposing party’s concessions

regarding any of the preliminary injunction prongs? After receiving a concession,

can the opposing party simply sandbag the movant on appeal, demanding proof of

a previously conceded prong? Indeed, the government can and does stipulate that

all of the prongs of a preliminary injunction have been met when it consents to

the entry of such an order. And this lack of clarity places the district court in an

-27-
impossible dilemma in the rush of injunctive litigation to decide what they can

and cannot rely on in the parties’ presentation of the case.

As with the Chevron issues discussed above, the en banc majority’s

decision to vacate the en banc order places litigants in an untenable position until

we offer further clarity.

III. Conclusion

Anyone who has seen a semiautomatic rifle equipped with a bump stock

understands it increases the rate of lethal fire. But Congress did not define

“machinegun” based upon the speed at which a firearm shoots or the firearm’s

potential for mass carnage. Section 5845(b) defined “machinegun” based on its

mechanical operation. The language of that statute and that statute alone is what

we must apply.

The en banc majority has done the circuit no favors today. By dismissing

the en banc order, the majority perpetuates confusion on difficult issues in the

circuit. We are left not knowing whether the government can waive Chevron,

whether the rule of lenity can ever trump Chevron, and whether formal

concessions concerning a preliminary injunction factor before the district court is

binding. For the sake of courts and future litigants who must wade through the

panel majority’s reasoning, I can only hope we receive clarity on these issues

sooner rather than later.

-28-
 For the foregoing reasons, I dissent from the majority’s decision to vacate

the en banc order.

-29-
19-4036, Aposhian v. Wilkinson, et al.

HARTZ, Circuit Judge, joined by TYMKOVICH, Chief Judge, and HOLMES, EID,
and CARSON, Circuit Judges, dissenting.

I am disappointed that the majority of the en banc court has voted not to consider

this matter. There are a variety of important issues raised in the appeal. The one of most

interest to me is whether the doctrine of Chevron U.S.A., Inc. v. Natural Resources

Defense Council, 467 U.S. 837 (1984), is at all in play.

The question here is whether a particular type of bump stock is a “machinegun” as

defined by 26 U.S.C. § 5845(b). This is a matter of statutory interpretation, inherently a

responsibility of the courts. As Chief Justice Marshall said more than two centuries ago,

“It is emphatically the province and duty of the judicial department to say what the law

is.” Marbury v. Madison, 5 U.S. 137, 177 (1803). Perhaps that sentence has been quoted

so much that it seems trite, but it is an essential starting point for the analysis in this

appeal.

I say “starting point” because there are qualifications to the general rule. Any

qualification, however, must be soundly grounded in a compelling rationale. One

qualification has been recognized in Chevron and the multitude of cases expounding on

it. Those cases inform us, instruct us, that in proper circumstances courts must defer to a

government agency’s interpretation of ambiguous statutory language. I question whether

such circumstances are present here.

At the end of 2018 the federal Bureau of Alcohol, Tobacco, Firearms, and

Explosives (ATF) promulgated a Final Rule interpreting the statutory definition of
“machinegun” to include bump stocks that the ATF had previously declared not to be

machine guns. The panel majority in this case held that it should defer to the definition in

the Final Rule under the Chevron doctrine. Its opinion carefully, and intelligently,

analyzed the Rule and its history and concluded that it was a legislative rule compelling

deference, rather than an interpretive rule entitled to no deference.

That opinion’s analysis, however, strikes me as formalistic. It does not explain

why this court should shirk its fundamental duty “to say what the law is.” As I

understand the Chevron line of cases, deference to an agency’s interpretation of an

ambiguous statute can be justified on either of two grounds. First, the statutory

ambiguity may signal congressional intent to delegate policymaking authority to an

agency within the bounds of the statutory language, and courts should defer to that policy

choice. Second, the complexity or technical difficulty of the subject matter may suggest

the wisdom of deferring to the experience and expertise of the agency in construing the

statute. If, however, the agency’s interpretation of the statute is based neither on a policy

judgment nor the application of agency expertise, deference cannot be justified. In

particular, if the agency has done nothing more than conduct an analysis typical of that

performed by the judiciary, there is no reason to defer. To be sure, agency lawyers may

well have legal minds superior to those of any member of the court construing the statute,

but that does not excuse disobedience to Article III’s requirements for one to be

empowered to exercise the functions of a federal judge. We must be the ones to perform

those tasks, although always grateful for assistance from the bar.

2
 The Final Rule is solely the product of the ATF’s performing a judge-like

interpretation of the statutory language. The agency disclaimed any policy-making

component to its analysis. Nor has it suggested that its departure from its prior publicly

expressed views on the legality of bump stocks was based on any new expert knowledge

or experience. Chevron deference is improper.

3
19-4036, Aposhian v. Wilkinson, et al.

EID, Circuit Judge, joined by TYMKOVICH, Chief Judge, and HARTZ, HOLMES,
and CARSON, Circuit Judges, dissenting.

Chevron has no place in this case. At least four reasons support this conclusion.

First, the statutory language is not ambiguous. Ante, at 9–12 (Tymkovich, C.J.,

dissenting); post, at 1–2 (Carson, J., dissenting). Second, even if the language were

ambiguous, the agency offers up no particular expertise or policy insight to help resolve

the ambiguity. Ante, at 1–3 (Hartz, J., dissenting). Third, any argument for deference is

waived because the agency disavows reliance on Chevron altogether. Ante, at 12–17

(Tymkovich, C.J., dissenting); post, at 2–3 (Carson, J., dissenting). Finally, the criminal

penalties at issue in this proceeding counsel against Chevron’s application. Ante, at 17–

25 (Tymkovich, C.J., dissenting). I join my dissenting colleagues, and write briefly to

elaborate on this latter point.

The panel majority rests the propriety of its application of Chevron in this context

on footnote 18 of Babbitt v. Sweet Home Chapter of Communities for a Great Oregon,

515 U.S. 687 (1995). Aposhian v. Barr, 958 F.3d 969, 982–83 (10th Cir. 2020). In the

footnote, the Supreme Court states that it has “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.” Babbitt, 515 U.S. at

704 n.18. The panel majority interprets this footnote as a directive from the Court to

apply Chevron in any case that involves both civil and criminal penalties. Aposhian, 958

F.3d at 983. But the footnote is not a mandate. Simply because the footnote may allow
application of Chevron when criminal penalties are involved does not mean that it

commands deference be applied. Cf. ante, at 24 (Tymkovich, C.J., dissenting)

(suggesting that the footnote does not create a categorical rule that Chevron trumps the

rule of lenity). Here, the fact that the statutory regime before us is predominantly

criminal in nature counsels against applying Chevron.

The Gun Control Act of 1968 (“GCA”), 18 U.S.C. § 921 et seq., as amended by

the Firearm Owners’ Protection Act, Pub. L. No. 99-308, 100 Stat. 449 (1986), imposes a

broad prohibition against owning a “machinegun,” making it “unlawful for any person to

transfer or possess a machinegun.” 18 U.S.C. § 922(o)(1); see Guedes v. Bureau of

Alcohol, Tobacco, Firearms & Explosives, 920 F.3d 1, 36 (D.C. Cir. 2019) (Henderson,

J., concurring in part and dissenting in part) (explaining that “private ownership of

machine guns” is “effectively banned” by the GCA). And to enforce this prohibition, the

GCA renders such unlawful possession a felony punishable by up to ten years of

imprisonment. 18 U.S.C. § 924(a)(2). Thus, the definition of “machinegun”—which the

GCA incorporates by reference from the National Firearms Act (“NFA”), 26 U.S.C.

§§ 5801–5872, see 18 U.S.C. § 921(a)(23) (incorporating the NFA’s definition into the

GCA)—has an enormous criminal impact. By contrast, the civil scope of the statutory

regime is quite limited. The GCA’s prohibition on “machineguns” is subject to only two

extremely limited exceptions, for “machineguns” (1) “transfer[red] to or by, or

possess[ed] by or under the authority of” the federal or a state government, id.

§ 922(o)(2)(A), or (2) lawfully possessed before the prohibition went into effect, id.

§ 922(o)(2)(B). Only “machineguns” that fall within these narrow exceptions are subject

2
to civil consequences, and even then, the civil consequences are limited—the chief

consequence is a registration requirement. See 26 U.S.C. §§ 5841, 5845(a), (b). Given

the breadth of the criminal prohibition and the limited nature of the exceptions giving rise

to civil ramifications, I conclude that the statutory regime is predominately criminal.

Because this case involves a predominately criminal proceeding, I would hold that

the agency’s interpretation of “machinegun” does not qualify for Chevron deference.

Criminal laws do not fall within the specialized expertise of any agency. True, the

executive branch enforces the federal criminal laws and prosecutes federal criminal cases.

But the Supreme Court has “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).

Moreover, deferring to an agency’s interpretation of a criminal statute would run

headlong into the constitutional concerns of fair notice and separation of powers. Ante, at

19–22 (Tymkovich, C.J., dissenting) (discussing concerns as related to the rule of lenity).

Indeed, the Court has made clear that “criminal laws are for courts, not for the

Government, to construe.” Abramski v. United States, 573 U.S. 169, 191 (2014). The

panel majority recognizes the Court’s statements but points out that they were made

outside of a “Chevron-eligible interpretation.” Aposhian, 958 F.3d at 984 (internal

quotation mark omitted) (quoting Guedes, 920 F.3d at 25). That fact, however, does not

mean the principles can be disregarded.

Chevron does not apply inexorably. It is a presumption about congressional

intent, grounded in considerations such as agency expertise and the preference for leaving

policy choices to Executive Branch officials who are politically accountable. Chevron

3
U.S.A. Inc. v. Nat. Res. Def. Council, Inc., 467 U.S. 837, 865 (1984). When these

essential premises are missing or there is otherwise reason to doubt that Congress

intended to delegate authority to an agency, Chevron does not apply. See Epic Sys. Corp.

v. Lewis, 138 S. Ct. 1612, 1629–30 (2018). See generally United States v. Mead Corp.,

533 U.S. 218 (2001). Here, there is ample reason to doubt that Congress would have

intended that deference be paid given the substantial criminal consequences at stake.

Because the statutory regime at issue regulates primarily through a criminal prohibition

with only limited civil ramifications, Chevron deference is misplaced. Accordingly, I

respectfully dissent.

4
19-4036, Aposhian v. Wilkinson, et al.

CARSON, Circuit Judge, joined by TYMKOVICH, Chief Judge, and HARTZ,
HOLMES, and EID, Circuit Judges, dissenting from the denial of rehearing en banc.

I join the well-reasoned dissents authored by Chief Judge Tymkovich, Judge Hartz

and Judge Eid. I write separately to emphasize a few points from my dissent to the panel

opinion.

I.

The National Firearms Act (“NFA”) is not ambiguous. It has been on the books

for nearly ninety years and its definition of a “machinegun” has proven workable.

Indeed, until the Executive developed an unfavorable opinion of nonmechanical

bumpstocks, the federal government blessed the devices as complying with the NFA on

many occasions. A legal device can be used to perpetrate horrific acts, but that does not

make it illegal and does not render the statutory definition allowing its possession

ambiguous. The NFA makes illegal the ownership of “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.” 26 U.S.C. § 5845(b). The

NFA speaks in terms of how a firearm functions, not its capability of firing rapidly or

causing harm. As I explain more fully in my dissent to the panel opinion, a semi-

automatic weapon equipped with a nonmechanical bumpstock requires the trigger to

function each time it fires. And it does not keep firing “automatically” when the operator

presses the trigger. So under the clear statutory language, a firearm equipped with a

nonmechanical bumpstock is definitionally not a prohibited machinegun. The panel
majority, in my opinion, clearly erred by determining the NFA’s definition of

“machinegun” is ambiguous.

II.

I also question the Court’s decision to vacate the en banc order when the parties’

thorough briefing identified an apparent intracircuit conflict about whether the

application of Chevron deference must be requested by the government in the first

instance. That concerns me, especially given that both the Supreme Court and our Circuit

have “often declined to apply Chevron deference when the government fails to invoke it”

or otherwise rely on it. Guedes v. Bureau of Alcohol, Tobacco, Firearms & Explosives,

140 S. Ct. 789, 790 (2020) (statement of Gorsuch, J., respecting denial of certiorari). See

also, e.g., Hays Med. Ctr. v. Azar, 956 F.3d 1247, 1264 n.18 (10th Cir. 2020); Hydro

Res., Inc. v. EPA, 608 F.3d 1131, 1146 (10th Cir. 2010). Indeed, as early as 2010, we

put the burden of asking for Chevron deference on the government. Id.

But here the panel opinion ignores Hydro Resources and instead relies on our later

decision in TransAm Trucking, Inc. v. U.S. Dep’t of Lab. Admin. Rev. Bd., 833 F.3d

1206, 1212 n.4 (10th Cir. 2016), where we relied on Chevron with no government request

that we do so. The panel’s reliance on TransAm violates the venerable circuit rule that

when faced with an intracircuit conflict, we should follow the earlier, settled precedent

and not the later decided case. United States v. Melendez-Garcia, 28 F.3d 1046, 1054

(10th Cir. 1994). And if the court wishes to jettison the older line of cases in favor of

more recent authority, that action requires invoking the machinery of the en banc court.

C.f. United States v. Taylor, 828 F.2d 630, 633 (10th Cir. 1987) (obtaining en banc

2
review for rejecting the first published decision in favor of subsequent contrary

authority).

The majority’s application of Chevron with no government request that it do so is

even more alarming in the context of this case. Here, the government expressly

disavowed any reliance on Chevron and, in fact, asked the panel not to apply it.1 “If the

justification for Chevron is that ‘“policy choices” should be left to executive branch

officials “directly accountable to the people,”’. . . then courts must equally respect the

Executive’s decision not to make policy choices in the interpretation of Congress’s

handiwork.” Guedes, 140 S. Ct. at 790 (statement of Gorsuch, J., respecting denial of

certiorari) (quoting Epic Sys. Corp. v. Lewis, 138 S. Ct. 1612, 1630 (2018)). Here, by

turning a blind eye to the government’s request and applying Chevron anyway, the

majority—unfairly in my opinion—sealed Mr. Aposhian’s fate by tipping the scales in

favor of the government.

III.

As a final point, I wish to emphasize that the panel majority (perhaps

inadvertently) has increased the burden on district courts in the preliminary injunction

context. Our preliminary injunction jurisprudence required Mr. Aposhian to demonstrate

four things to the district court—one of which was that he would suffer irreparable harm

if the injunction did not issue. As is common in litigation, the government conceded that

1
The district court noted that the government “defendants went out of their way to
avoid citing Chevron and its progeny and repeatedly stressed that they neither request nor
believe their interpretations are entitled to any measure of deference.”
3
if a preliminary injunction did not issue, Mr. Aposhian would suffer irreparable harm.

He, therefore, presented no evidence on that issue and the district court denied the request

for preliminary injunction based on another ground.

Despite the clarity with which the government conceded the irreparable harm

element and Mr. Aposhian’s reasonable reliance on that concession, the panel majority

concluded that he failed to meet his burden, in part, because he did not show irreparable

harm. I view the panel majority’s conclusion as contrary to our caselaw, unfair, and as

impeding judicial economy. Here’s why.

Trial courts are busy places and their judges are tasked with making decisions and

moving cases in a swift and efficient manner. To assist the administration of their busy

dockets, judges encourage parties to focus on the areas in dispute. The parties in turn do

things like stipulate to facts or concede certain elements of a claim. We, as an appellate

court, encourage these practices and routinely hold parties to the stipulations and

concessions they make in federal district courts. See, e.g., Johnson v. Spencer, 950 F.3d

680, 708 (10th Cir. 2020) (concluding that defendants who had relied on claim preclusion

as a defense met their burden of proof on two of the three requisite elements because the

opposing party “concede[d] . . . the second and third elements”); United States v. Sinks,

473 F.3d 1315, 1321 (10th Cir. 2007) (observing that the government can concede

elements of the plain error standard of review, which a criminal defendant has the burden

of proof to establish). We have even held, in the preliminary injunction context, that the

parties can stipulate to the entry of a preliminary injunction—which necessarily means

4
they concede that the applicant can prove all the elements required to receive the

injunction.2

As this shows, the panel’s decision conflicts with our caselaw which allows the

district court to accept as proven an element to which the opposing party stipulates. The

panel’s decision impedes judicial economy because going forward, parties will now have

to spend time and resources proving elements about which there is no dispute. And it is

unfair because the panel departed from common practice and our established caselaw

with no notice to Mr. Aposhian.

2
And this invites the question—if you can concede all the elements required for
injunctive relief, why can’t you concede just one? Obviously—you can.
5