(Slip Opinion) OCTOBER TERM, 2020 1
Syllabus
NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
being done in connection with this case, at the time the opinion is issued.
The syllabus constitutes no part of the opinion of the Court but has been
prepared by the Reporter of Decisions for the convenience of the reader.
See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.
SUPREME COURT OF THE UNITED STATES
Syllabus
UNITED STATES v. COOLEY
CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
THE NINTH CIRCUIT
No. 19–1414. Argued March 23, 2021—Decided June 1, 2021
Late one night Officer James Saylor of the Crow Police Department ap-
proached a truck parked on United States Highway 212, a public right-
of-way within the Crow Reservation in the State of Montana. Saylor
spoke to the driver, Joshua James Cooley, and observed that Cooley
appeared to be non-native and had watery, bloodshot eyes. Saylor also
noticed two semiautomatic rifles lying on Cooley’s front seat. Fearing
violence, Saylor ordered Cooley out of the truck and conducted a
patdown search. Saylor also saw in the truck a glass pipe and a plastic
bag that contained methamphetamine. Additional officers, including
an officer with the federal Bureau of Indian Affairs, arrived on the
scene in response to Saylor’s call for assistance. Saylor was directed
to seize all contraband in plain view, leading Saylor to discover more
methamphetamine. Saylor took Cooley to the Crow Police Department
where federal and local officers further questioned Cooley. Subse-
quently, a federal grand jury indicted Cooley on drug and gun offenses.
The District Court granted Cooley’s motion to suppress the drug evi-
dence. The Ninth Circuit affirmed. It reasoned that a tribal police
officer could stop (and hold for a reasonable time) a non-Indian suspect
if the officer first tries to determine whether the suspect is non-Indian
and, in the course of doing so, finds an apparent violation of state or
federal law. The Ninth Circuit concluded that Saylor had failed to
make that initial determination here.
Held: A tribal police officer has authority to detain temporarily and to
search non-Indian persons traveling on public rights-of-way running
through a reservation for potential violations of state or federal law.
Pp. 3–9.
(a) As a “general proposition,” the “inherent sovereign powers of an
Indian tribe do not extend to the activities of nonmembers of the tribe.”
2 UNITED STATES v. COOLEY
Syllabus
Montana v. United States, 450 U. S. 544, 565. The Court identified in
Montana two exceptions to that general rule, the second of which fits
almost like a glove here: A tribe retains inherent authority over the
conduct of non-Indians on the reservation “when that conduct threat-
ens or has some direct effect on . . . the health or welfare of the tribe.”
Id., at 566. The conclusion that Saylor’s actions here fall within Mon-
tana’s second exception is consistent with the Court’s prior Montana
cases. See Strate v. A–1 Contractors, 520 U. S. 438, 456 n. 11; see also
Atkinson Trading Co. v. Shirley, 532 U. S. 645, 651. Similarly, the
Court has held that when the “jurisdiction to try and punish an of-
fender rests outside the tribe, tribal officers may exercise their power
to detain the offender and transport him to the proper authorities.”
Duro v. Reina, 495 U. S. 676, 697. Ancillary to the authority to
transport a non-Indian suspect is the authority to search that individ-
ual prior to transport, as several state courts and other federal courts
have held. While that authority has sometimes been traced to a tribe’s
right to exclude non-Indians, tribes “have inherent sovereignty inde-
pendent of th[e] authority arising from their power to exclude,” Bren-
dale v. Confederated Tribes and Bands of Yakima Nation, 492 U. S.
408, 425 (plurality opinion), and here Montana’s second exception rec-
ognizes that inherent authority. In addition, recognizing a tribal of-
ficer’s authority to investigate potential violations of state or federal
laws that apply to non-Indians whether outside a reservation or on a
public right-of-way within the reservation protects public safety with-
out implicating the concerns about applying tribal laws to non-Indians
noted in the Court’s prior cases. Finally, the Court doubts the worka-
bility of the Ninth Circuit’s standards, which would require tribal of-
ficers first to determine whether a suspect is non-Indian and, if so, to
temporarily detain a non-Indian only for “apparent” legal violations.
919 F. 3d 1135, 1142. The first requirement produces an incentive to
lie. The second requirement introduces a new standard into search
and seizure law and creates a problem of interpretation that will arise
frequently given the prevalence of non-Indians in Indian reservations.
Pp. 3–7.
(b) Cooley’s arguments against recognition of inherent tribal sover-
eignty here are unpersuasive. While the Court agrees the Montana
exceptions should not be interpreted so as to “ ‘swallow the rule,’ ”
Plains Commerce Bank v. Long Family Land & Cattle Co., 554 U. S.
316, 330, this case does not raise that concern due to the close fit be-
tween Montana’s second exception and the facts here. In addition, the
Court sees nothing in existing federal cross-deputization statutes that
suggests Congress has sought to deny tribes the authority at issue. To
the contrary, existing legislation and executive action appear to oper-
ate on the assumption that tribes have retained this authority. Pp. 8–9.
Cite as: 593 U. S. ____ (2021) 3
Syllabus
919 F. 3d 1135, vacated and remanded.
BREYER, J., delivered the opinion for a unanimous Court. ALITO, J.,
filed a concurring opinion.
Cite as: 593 U. S. ____ (2021) 1
Opinion of the Court
NOTICE: This opinion is subject to formal revision before publication in the
preliminary print of the United States Reports. Readers are requested to
notify the Reporter of Decisions, Supreme Court of the United States, Wash-
ington, D. C. 20543, of any typographical or other formal errors, in order that
corrections may be made before the preliminary print goes to press.
SUPREME COURT OF THE UNITED STATES
_________________
No. 19–1414
_________________
UNITED STATES, PETITIONER v. JOSHUA JAMES
COOLEY
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE NINTH CIRCUIT
[June 1, 2021]
JUSTICE BREYER delivered the opinion of the Court.
The question presented is whether an Indian tribe’s po-
lice officer has authority to detain temporarily and to
search a non-Indian on a public right-of-way that runs
through an Indian reservation. The search and detention,
we assume, took place based on a potential violation of state
or federal law prior to the suspect’s transport to the proper
nontribal authorities for prosecution.
We have previously noted that a tribe retains inherent
sovereign authority to address “conduct [that] threatens or
has some direct effect on . . . the health or welfare of the
tribe.” Montana v. United States, 450 U. S. 544, 566 (1981);
see also Strate v. A–1 Contractors, 520 U. S. 438, 456, n. 11
(1997). We believe this statement of law governs here. And
we hold the tribal officer possesses the authority at issue.
I
Late at night in February 2016, Officer James Saylor of
the Crow Police Department was driving east on United
States Highway 212, a public right-of-way within the Crow
Reservation, located within the State of Montana. Saylor
saw a truck parked on the westbound side of the highway.
2 UNITED STATES v. COOLEY
Opinion of the Court
Believing the occupants might need assistance, Saylor ap-
proached the truck and spoke to the driver, Joshua James
Cooley. Saylor noticed that Cooley had “watery, bloodshot
eyes” and “appeared to be non-native.” App. to Pet. for Cert.
95a. Saylor also noticed two semiautomatic rifles lying on
the front seat. Eventually fearing violence, Saylor ordered
Cooley out of the truck and conducted a patdown search.
He called tribal and county officers for assistance. While
waiting for the officers to arrive, Saylor returned to the
truck. He saw a glass pipe and plastic bag that contained
methamphetamine. The other officers, including an officer
with the federal Bureau of Indian Affairs, then arrived.
They directed Saylor to seize all contraband in plain view,
leading him to discover more methamphetamine. Saylor
took Cooley to the Crow Police Department where federal
and local officers further questioned Cooley.
In April 2016, a federal grand jury indicted Cooley on
drug and gun offenses. See 21 U. S. C. §841(a)(1); 18
U. S. C. §924(c)(1)(A). The District Court granted Cooley’s
motion to suppress the drug evidence that Saylor had
seized. It reasoned that Saylor, as a Crow Tribe police of-
ficer, lacked the authority to investigate nonapparent vio-
lations of state or federal law by a non-Indian on a public
right-of-way crossing the reservation.
The Government appealed. See 18 U. S. C. §3731. The
Ninth Circuit affirmed the District Court’s evidence-
suppression determination. The Ninth Circuit panel wrote
that tribes “cannot exclude non-Indians from a state or fed-
eral highway” and “lack the ancillary power to investigate
non-Indians who are using such public rights-of-way.” 919
F. 3d 1135, 1141 (2019). It added that a tribal police officer
nonetheless could stop (and hold for a reasonable time) a
non-Indian suspect, but only if (1) the officer first tried to
determine whether “the person is an Indian,” and, if the
person turns out to be a non-Indian, (2) it is “apparent” that
the person has violated state or federal law. Id., at 1142.
Cite as: 593 U. S. ____ (2021) 3
Opinion of the Court
Non-Indian status, the panel added, can usually be deter-
mined by “ask[ing] one question.” Ibid. (internal quotation
marks omitted). Because Saylor had not initially tried to
determine whether Cooley was an Indian, the panel held
that the lower court correctly suppressed the evidence.
The Ninth Circuit denied the Government’s request for
rehearing en banc. We then granted the Government’s pe-
tition for certiorari in order to decide whether a tribal police
officer has authority to detain temporarily and to search
non-Indians traveling on public rights-of-way running
through a reservation for potential violations of state or fed-
eral law.
II
Long ago we described Indian tribes as “distinct, inde-
pendent political communities” exercising sovereign au-
thority. Worcester v. Georgia, 6 Pet. 515, 559 (1832). Due
to their incorporation into the United States, however, the
“sovereignty that the Indian tribes retain is of a unique and
limited character.” United States v. Wheeler, 435 U. S. 313,
323 (1978). Indian tribes may, for example, determine
tribal membership, regulate domestic affairs among tribal
members, and exclude others from entering tribal land.
See, e.g., Plains Commerce Bank v. Long Family Land &
Cattle Co., 554 U. S. 316, 327–328 (2008). On the other
hand, owing to their “dependent status,” tribes lack any
“freedom independently to determine their external rela-
tions” and cannot, for instance, “enter into direct commer-
cial or governmental relations with foreign nations.”
Wheeler, 435 U. S., at 326. Tribes also lack inherent sover-
eign power to exercise criminal jurisdiction over non-
Indians. See Oliphant v. Suquamish Tribe, 435 U. S. 191,
212 (1978). In all cases, tribal authority remains subject to
the plenary authority of Congress. See, e.g., Michigan v.
Bay Mills Indian Community, 572 U. S. 782, 788 (2014).
Here, no treaty or statute has explicitly divested Indian
4 UNITED STATES v. COOLEY
Opinion of the Court
tribes of the policing authority at issue. We turn to prece-
dent to determine whether a tribe has retained inherent
sovereign authority to exercise that power. In answering
this question, our decision in Montana v. United States, 450
U. S. 544 (1981), is highly relevant. In that case we asked
whether a tribe could regulate hunting and fishing by non-
Indians on land that non-Indians owned in fee simple on a
reservation. We held that it could not. We supported our
conclusion by referring to our holding in Oliphant that a
tribe could not “exercise criminal jurisdiction over non-
Indians.” Montana, 450 U. S., at 565. We then wrote that
the “principles on which [Oliphant] relied support the gen-
eral proposition that the inherent sovereign powers of an
Indian tribe do not extend to the activities of nonmembers
of the tribe.” Ibid.
At the same time, we made clear that Montana’s “general
proposition” was not an absolute rule. Ibid. We set forth
two important exceptions. First, we said that a “tribe may
regulate, through taxation, licensing, or other means, the
activities of nonmembers who enter consensual relation-
ships with the tribe or its members, through commercial
dealing, contracts, leases, or other arrangements.” Ibid.
Second, we said that a “tribe may also retain inherent
power to exercise civil authority over the conduct of non-
Indians on fee lands within its reservation when that con-
duct threatens or has some direct effect on the political in-
tegrity, the economic security, or the health or welfare of the
tribe.” Id., at 566 (emphasis added).
The second exception we have just quoted fits the present
case, almost like a glove. The phrase speaks of the protec-
tion of the “health or welfare of the tribe.” To deny a tribal
police officer authority to search and detain for a reasonable
time any person he or she believes may commit or has com-
mitted a crime would make it difficult for tribes to protect
themselves against ongoing threats. Such threats may be
Cite as: 593 U. S. ____ (2021) 5
Opinion of the Court
posed by, for instance, non-Indian drunk drivers, transport-
ers of contraband, or other criminal offenders operating on
roads within the boundaries of a tribal reservation. As the
Washington Supreme Court has noted, “[a]llowing a known
drunk driver to get back in his or her car, careen off down
the road, and possibly kill or injure Indians or non-Indians
would certainly be detrimental to the health or welfare of
the Tribe.” State v. Schmuck, 121 Wash. 2d 373, 391, 850
P. 2d 1332, 1341, cert. denied, 510 U. S. 931 (1993).
We have subsequently repeated Montana’s proposition
and exceptions in several cases involving a tribe’s jurisdic-
tion over the activities of non-Indians within the reserva-
tion. See, e.g., Plains Commerce Bank, 554 U. S., at 328–
330; Nevada v. Hicks, 533 U. S. 353, 358–360, and n. 3
(2001); South Dakota v. Bourland, 508 U. S. 679, 694–696
(1993); Duro v. Reina, 495 U. S. 676, 687–688 (1990); Bren-
dale v. Confederated Tribes and Bands of Yakima Nation,
492 U. S. 408, 426–430 (1989) (plurality opinion). In doing
so we have reserved a tribe’s inherent sovereign authority
to engage in policing of the kind before us. Most notably, in
Strate v. A–1 Contractors, 520 U. S. 438, 456–459 (1997),
we relied upon Montana’s general jurisdiction-limiting
principle to hold that tribal courts did not retain inherent
authority to adjudicate personal-injury actions against non-
members of the tribe based upon automobile accidents that
took place on public rights-of-way running through a reser-
vation. But we also said:
“We do not here question the authority of tribal police
to patrol roads within a reservation, including rights-
of-way made part of a state highway, and to detain and
turn over to state officers nonmembers stopped on the
highway for conduct violating state law. Cf. State v.
Schmuck, 121 Wash. 2d 373, 390, 850 P. 2d 1332, 1341
(en banc) (recognizing that a limited tribal power ‘to
stop and detain alleged offenders in no way confers an
6 UNITED STATES v. COOLEY
Opinion of the Court
unlimited authority to regulate the right of the public
to travel on the Reservation’s roads’), cert. denied, 510
U. S. 931 (1993).” 520 U. S., at 456, n. 11.
We reiterated this point in Atkinson Trading Co. v. Shirley,
532 U. S. 645, 651 (2001), there confirming that Strate “did
not question the ability of tribal police to patrol the high-
way.”
Similarly, we recognized in Duro that “[w]here jurisdic-
tion to try and punish an offender rests outside the tribe,
tribal officers may exercise their power to detain the of-
fender and transport him to the proper authorities.” 495
U. S., at 697. The authority to search a non-Indian prior to
transport is ancillary to this authority that we have already
recognized. Cf. Ortiz-Barraza v. United States, 512 F. 2d
1176, 1180–1181 (CA9 1975). Indeed, several state courts
and other federal courts have held that tribal officers pos-
sess the authority at issue here. See, e.g., Schmuck, 121
Wash. 2d, at 390, 850 P. 2d, at 1341; State v. Pamperien,
156 Ore. App. 153, 155–159, 967 P. 2d 503, 504–506 (1998);
State v. Ryder, 98 N. M. 453, 456, 649 P. 2d 756, 759 (1982);
see also United States v. Terry, 400 F. 3d 575, 579–580 (CA8
2005); Ortiz-Barraza, 512 F. 2d, at 1180–1181; see gener-
ally F. Cohen, Handbook of Federal Indian Law §9.07, p.
773 (2012). To be sure, in Duro we traced the relevant tribal
authority to a tribe’s right to exclude non-Indians from res-
ervation land. See 495 U. S., at 696–697. But tribes “have
inherent sovereignty independent of th[e] authority arising
from their power to exclude,” Brendale, 492 U. S., at 425
(plurality opinion), and here Montana’s second exception
recognizes that inherent authority.
We also note that our prior cases denying tribal jurisdic-
tion over the activities of non-Indians on a reservation have
rested in part upon the fact that full tribal jurisdiction
would require the application of tribal laws to non-Indians
who do not belong to the tribe and consequently had no say
Cite as: 593 U. S. ____ (2021) 7
Opinion of the Court
in creating the laws that would be applied to them. See
Duro, 495 U. S., at 693 (noting the concern that tribal-court
criminal jurisdiction over nonmembers would subject such
defendants to “trial by political bodies that do not include
them”); Plains Commerce Bank, 554 U. S., at 337 (noting
that nonmembers “have no part in tribal government” and
have “no say in the laws and regulations that govern tribal
territory”). Saylor’s search and detention, however, do not
subsequently subject Cooley to tribal law, but rather only
to state and federal laws that apply whether an individual
is outside a reservation or on a state or federal highway
within it. As the Solicitor General points out, an initial in-
vestigation of non-Indians’ “violations of federal and state
laws to which those non-Indians are indisputably subject”
protects the public without raising “similar concerns” of the
sort raised in our cases limiting tribal authority. Brief for
United States 24–25.
Finally, we have doubts about the workability of the
standards that the Ninth Circuit set out. Those standards
require tribal officers first to determine whether a suspect
is non-Indian and, if so, allow temporary detention only if
the violation of law is “apparent.” 919 F. 3d, at 1142. The
first requirement, even if limited to asking a single ques-
tion, would produce an incentive to lie. The second require-
ment—that the violation of law be “apparent”—introduces
a new standard into search and seizure law. Whether, or
how, that standard would be met is not obvious. At the
same time, because most of those who live on Indian reser-
vations are non-Indians, this problem of interpretation
could arise frequently. See, e.g., Brief for Former United
States Attorneys as Amici Curiae 24 (noting that 3.5 million
of the 4.6 million people living in American Indian areas in
the 2010 census were non-Indians); Brief for National In-
digenous Women’s Resource Center et al. as Amici Curiae
19–20 (noting that more than 70% of residents on several
reservations are non-Indian).
8 UNITED STATES v. COOLEY
Opinion of the Court
III
In response, Cooley cautions against “inappropriately ex-
pand[ing] the second Montana exception.” Brief for Re-
spondent 24–25 (citing Atkinson, 532 U. S., at 657, n. 12,
and Strate, 520 U. S., at 457–458). We have previously
warned that the Montana exceptions are “limited” and “can-
not be construed in a manner that would swallow the rule.”
Plains Commerce Bank, 554 U. S., at 330 (internal quota-
tion marks omitted). But we have also repeatedly acknowl-
edged the existence of the exceptions and preserved the pos-
sibility that “certain forms of nonmember behavior” may
“sufficiently affect the tribe as to justify tribal oversight.”
Id., at 335. Given the close fit between the second exception
and the circumstances here, we do not believe the warnings
can control the outcome.
Cooley adds that federal cross-deputization statutes al-
ready grant many Indian tribes a degree of authority to en-
force federal law. See Brief for Respondent 28–30; see gen-
erally 25 U. S. C. §§2803(5), (7) (Secretary of the Interior
may authorize tribal officers to “make inquiries of any per-
son” related to the “carrying out in Indian country” of fed-
eral law and to “perform any other law enforcement related
duty”); §2805 (Secretary of the Interior may promulgate
rules “relating to the enforcement of ” federal criminal law
in Indian country); 25 CFR §12.21 (2019) (Bureau of Indian
Affairs may “issue law enforcement commissions” to tribal
police officers “to obtain active assistance” in enforcing fed-
eral criminal law). Because Congress has specified the
scope of tribal police activity through these statutes, Cooley
argues, the Court must not interpret tribal sovereignty to
fill any remaining gaps in policing authority. See Brief for
Respondent 12.
We are not convinced by this argument. The statutory
and regulatory provisions to which Cooley refers do not eas-
ily fit the present circumstances. They are overinclusive,
for instance encompassing the authority to arrest. See
Cite as: 593 U. S. ____ (2021) 9
Opinion of the Court
§2803(3). And they are also underinclusive. Because these
provisions do not govern violations of state law, tribes
would still need to strike agreements with a variety of other
authorities to ensure complete coverage. See Brief for Ca-
yuga Nation et al. as Amici Curiae 7–8, 25–27. More
broadly, cross-deputization agreements are difficult to
reach, and they often require negotiation between other au-
thorities and the tribes over such matters as training, re-
ciprocal authority to arrest, the “geographical reach of the
agreements, the jurisdiction of the parties, liability of offic-
ers performing under the agreements, and sovereign im-
munity.” Fletcher, Fort, & Singel, Indian Country Law En-
forcement and Cooperative Public Safety Agreements, 89
Mich. Bar J. 42, 44 (2010).
In short, we see nothing in these provisions that shows
that Congress sought to deny tribes the authority at issue,
authority that rests upon a tribe’s retention of sovereignty
as interpreted by Montana, and in particular its second ex-
ception. To the contrary, in our view, existing legislation
and executive action appear to operate on the assumption
that tribes have retained this authority. See, e.g., Brief for
Current and Former Members of Congress as Amici Curiae
23–25; Brief for Former U. S. Attorneys as Amici Curiae
28–29.
* * *
For these reasons, we vacate the Ninth Circuit’s judg-
ment and remand the case for further proceedings con-
sistent with this opinion.
It is so ordered.
Cite as: 593 U. S. ____ (2021) 1
ALITO, J., concurring
SUPREME COURT OF THE UNITED STATES
_________________
No. 19–1414
_________________
UNITED STATES, PETITIONER v. JOSHUA JAMES
COOLEY
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE NINTH CIRCUIT
[June 1, 2021]
JUSTICE ALITO, concurring.
I join the opinion of the Court on the understanding that
it holds no more than the following: On a public right-of-
way that traverses an Indian reservation and is primarily
patrolled by tribal police, a tribal police officer has the au-
thority to (a) stop a non-Indian motorist if the officer has
reasonable suspicion that the motorist may violate or has
violated federal or state law, (b) conduct a search to the ex-
tent necessary to protect himself or others, and (c) if the
tribal officer has probable cause, detain the motorist for the
period of time reasonably necessary for a non-tribal officer
to arrive on the scene.