Amicus Curiae Brief — William Trevor Case, Petitioner v. Montana

No. 24-624

IN THE

Supreme Court of the United States

WILLIAM TREVOR CASE,

Petitioner,

v.

MONTANA

Respondent.

ON WRIT OF CERTIORARI

TO THE MONTANA SUPREME COURT

BRIEF OF THE MONTANA ASSOCIATION OF

CRIMINAL DEFENSE LAWYERS AS AMICUS

CURIAE IN SUPPORT OF PETITIONER

DAVID F. NESS

FEDERAL DEFENDERS OF

MONTANA

104 Second Street South,

Ste. 301

Great Falls, MT 59401

KUFERE J. LAING

MARK S. DAVIES

Counsel of Record

WHITE & CASE LLP

701 Thirteenth Street NW

Washington, D.C. 20005

(202) 626-3600

mark.davies@whitecase.com

JAMES P. BUTLER

WHITE & CASE LLP

75 State Street

Boston, MA 02109

August 6, 2025

Counsel for Amicus Curiae

i

TABLE OF CONTENTS

Page(s)

INTEREST OF THE AMICUS CURIAE................ 1

SUMMARY OF THE ARGUMENT ........................ 2

ARGUMENT ........................................................... 3

I.

The Fourth Amendment requires all home

entries to be supported by probable cause....... 3

II. Reasonable suspicion applies in the context of

street policing, not home entries. ..................... 8

III. A reasonable suspicion standard interferes

with the Second Amendment’s right to bear

arms in the home. ........................................... 12

CONCLUSION ...................................................... 19

ii

TABLE OF AUTHORITIES

Page(s)

Cases

Bailey v. Kennedy,

349 F.3d 731 (4th Cir. 2003) ................................ 18

Brigham City v. Stuart,

547 U.S. 398 (2006) ........................................ 4, 5, 6

Bruce v. Guernsey,

777 F.3d 872 (7th Cir. 2015) ................................ 18

Chamberlain v. City of White Plains,

960 F.3d 100 (2d Cir. 2020) ................... 7, 8, 14, 15

Collins v. Virginia,

584 U.S. 586 (2018) ............................................ 3, 9

Corrigan v. District of Columbia,

841 F.3d 1022 (D.C. Cir. 2016) ............................ 14

District of Columbia v. Heller,

554 U.S. 570 (2008) .......................................... 3, 13

Florida v. Jardines,

569 U.S. 1 (2013) .............................................. 3, 11

Georgia v. Randolph,

547 U.S. 103 (2006) .......................................... 4, 13

Hill v. Walsh,

884 F.3d 16 (1st Cir. 2018) .................................... 9

Illinois v. Wardlow,

528 U.S. 119 (2000) .............................................. 10

iii

Johnson v. United States,

333 U.S. 10 (1948) .............................................. 2, 7

Kanter v. Barr,

919 F.3d 437 (7th Cir. 2019) .......................... 15, 16

Katz v. United States,

389 U.S. 347 (1967) ................................................ 7

Kentucky v. King,

563 U.S. 452 (2011) ............................................ 2, 4

Kirk v. Louisiana,

536 U.S. 635 (2002) ............................................ 2, 5

McDonald v. City of Chicago,

561 U.S. 742 (2010) .............................................. 13

Michigan v. Tyler,

436 U.S. 499 (1978) ...................................... 6, 8, 12

Mincey v. Arizona,

437 U.S. 385 (1978) ............................................ 5, 8

Minnesota v. Olson,

495 U.S. 91 (1990) .................................................. 6

Ornelas v. United States,

517 U.S. 690 (1996) .............................................. 10

Payton v. New York,

445 U.S. 573 (1980) ...................................... 4, 5, 11

Range v. Att’y Gen. of the U.S.,

69 F.4th 96 (3d Cir. 2023) (en banc) .................... 16

iv

Silverman v. United States,

365 U.S. 505 (1961) .............................. 3, 12, 13, 17

Terry v. Ohio,

392 U.S. 1 (1968) ........................................ 3, 10, 11

United States v. Duarte,

137 F.4th 743 (9th Cir. 2025) ........................ 15, 17

United States v. Jackson,

110 F.4th 1120 (8th Cir. 2024) ............................ 17

United States v. Najar,

451 F.3d 710 (10th Cir. 2006) .............................. 15

United States v. Quarterman,

877 F.3d 794 (8th Cir. 2017) .......................... 15, 17

United States v. Rahimi,

602 U.S. 680 (2024) .............................................. 16

United States v. Snipe,

515 F.3d 947 (9th Cir. 2008) ................................ 15

United States v. U.S. Dist. Ct.,

407 U.S. 297 (1972) ................................................ 4

United States v. Watson,

423 U.S. 411 (1976) .............................................. 11

Wayne v. United States,

318 F.2d 205 (D.C. Cir. 1963) ........................... 2, 7

Wyoming v. Houghton,

526 U.S. 295 (1999) ................................................ 7

v

Federal Statutes

Gun Control Act,

18 U.S.C. § 922(g)(1) ................................ 15, 16, 17

Other Authorities

Heather McCracken et al., Gun Ownership in

America, RAND

https://tinyurl.com/RANDGP (2020). .................. 17

INTEREST OF THE AMICUS CURIAE1

The Montana Association of Criminal Defense

Lawyers (MTACDL) is an affiliate of the National

Association of Criminal Defense Lawyers. The

MTACDL was formed to ensure justice and due

process for persons accused of crimes, to foster the

integrity, independence, and expertise of the criminal

defense profession, and to promote the proper and fair

administration of criminal justice. MTACDL files

amicus briefs in state and federal courts on the

request of its membership and at the request of the

courts seeking to provide assistance in cases that

present issues of broad importance to criminal

defendants, criminal defense lawyers, and the

criminal justice system as a whole.

MTACDL is keenly interested in Fourth

Amendment jurisprudence, particularly in the context

and the scope of exceptions to the warrant

requirement, and the prospect of authority for

ostensibly non-criminal investigative searches

serving as a tool for evading the warrant requirement

for criminal investigations.

1 Pursuant to Supreme Court Rule 37.6, Amicus states that this

brief was prepared in its entirety by amicus curiae and its

counsel. No monetary contribution toward the preparation or

submission of this brief was made by any person other than

amicus curiae and its counsel.

2

SUMMARY OF THE ARGUMENT

Since Payton nearly fifty years ago, it has been

plain: “police officers need either a warrant or

probable cause plus exigent circumstances in order to

make a lawful entry into a home.” Kirk v. Louisiana,

536 U.S. 635, 638 (2002) (citing Payton v. New York,

445 U.S. 573, 590 (1980)). Payton’s rule comports with

common sense. A warrant reflects a magistrate’s

detached and neutral judgment that a government

official has established probable cause and may enter

a home. Johnson v. United States, 333 U.S. 10, 13–14

(1948).

True, sometimes exigent circumstances require

immediate action: “People could well die in

emergencies if police tried to act with the calm

deliberation associated with the judicial process.”

Wayne v. United States, 318 F.2d 205, 212 (D.C. Cir.

1963) (Burger, J.). Thus, when an emergency

presents, “it [is] reasonable, within the meaning of the

Fourth Amendment, to dispense with the warrant

requirement.” Kentucky v. King, 563 U.S. 452, 462

(2011). But it is never reasonable to dispense of the

Fourth Amendment’s demand any entry into the

home must be supported by probable cause probable

cause.

I. When it comes to the home, the Fourth

Amendment does not make any compromises: If there

is no probable cause, there is no entry.

II. The Montana Supreme Court, and its sister

jurisdictions that permit warrantless entries into the

home based on reasonable suspicion, are wrong. The

reasonable suspicion standard arises from Terry v.

Ohio; it is limited to street policing and analogous

3

contexts. 392 U.S. 1, 9 (1968). But “when it comes to

the Fourth Amendment, the home is first among

equals.” Florida v. Jardines, 569 U.S. 1, 6 (2013).

Reasonable suspicion has no place in the home.

III. The Fourth Amendment also shares a close

relationship with the Second Amendment. See District

of Columbia v. Heller, 554 U.S. 570, 579 (2008). Both

Amendments reflect a person’s natural right to be safe

in—and to protect—their castle. See Silverman v.

United States, 365 U.S. 505, 511 n.4 (1961); see also

Heller, 554 U.S. at 628. In this case, and in many

others, police enter homes without a warrant based on

mere suspicion of an emergency because a gun is in

the home. That is wrong under the Fourth

Amendment. And it weakens the Second

Amendment’s protections too. The reasonable

suspicion standard places the Fourth Amendment and

Second Amendment at war.

ARGUMENT

I.

The Fourth Amendment requires all home

entries to be supported by probable cause.

1. The Fourth Amendment’s “very core” is “the

right of a man to retreat into his own home and there

be free from unreasonable governmental intrusion.”

Collins v. Virginia, 584 U.S. 586, 592 (2018) (citation

omitted). Indeed, “physical entry of the home is the

chief evil against which the wording of the Fourth

Amendment is directed.” United States v. U.S. Dist.

Ct., 407 U.S. 297, 313 (1972). The Fourth Amendment

thus draws “a firm line at the entrance to the house.”

Payton v. New York, 445 U.S. 573, 590 (1980). Without

consent or exigent circumstances—exceptions that

4

are “jealously and carefully drawn,” Georgia v.

Randolph, 547 U.S. 103, 109 (2006) (citation

omitted)—government intrusions into the home

require a particularized warrant “supported by

probable cause,” Payton, 445 U.S. at 584.

But “[n]othing in the Fourth Amendment” forbids

an officer from carrying out their duty to “prevent[]

violence,” “restor[e] order,” and “render[] first aid to

casualties.” Brigham City v. Stuart, 547 U.S. 398, 406

(2006). Indeed, “the ultimate touchstone of the Fourth

Amendment is reasonableness.” Id. at 403. Sometimes

“it [is] reasonable, within the meaning of the Fourth

Amendment, to dispense with the warrant

requirement.” Kentucky v. King, 563 U.S. 452, 462

(2011).

To ensure that the exigent circumstances

exception remains an exception, it is “strictly

circumscribed,” Georgia v. Randolph, 547 U.S. 103,

113 n.3 (2006) (citation omitted), and must “be

supported by a genuine exigency,” King, 563 U.S. at

470. In Brigham City, for example, the Court held that

the exigency of “emergency aid” requires officers to

have “an objectively reasonable basis for believing

that an occupant is seriously injured or imminently

threatened with such injury.” Brigham City v. Stuart,

547 U.S. 398, 400, 402 (2006). That is, the police must

“reasonably believe that a person within is in need of

immediate aid” and therefore must quickly act “to

protect or preserve life or avoid serious injury.”

Mincey, 437 U.S. at 392. Or put simply, certain

emergencies demand immediate action—if the Fourth

Amendment were to handcuff an officer in these

circumstances, that would be unreasonable.

5

2. The probable cause requirement is

uncompromising. It persists even in the face of exigent

circumstances. See Kirk v. Louisiana, 536 U.S. 635,

638 (2002). Payton is instructive. 445 U.S. at 590. At

issue there was whether a state statute that

authorized officers to “enter a private residence

without a warrant … to make a routine felony arrest”

violated the Fourth Amendment. Id. at 574. After

surveying the Founding-era common law, the Court

reiterated “the well-settled common-law rule that a

warrantless arrest in a public place is valid if the

arresting officer had probable cause to believe the

suspect is a felon.” Id. at 590 (citing United States v.

Watson, 423 U.S. 411 (1976)). But because “the Fourth

Amendment has drawn a firm line at the entrance to

the house,” a warrantless arrest in the home is

unreasonable “[a]bsent exigent circumstances.” Id.

“Payton makes plain, police officers need either a

warrant or probable cause plus exigent circumstances

in order to make a lawful entry into a home.” Kirk, 536

U.S. at 638.

Brigham City adheres to Payton’s plain rule. That

case arose “out of a melee that occurred … [a]t about

3 a.m.” Brigham City v. Stuart, 547 U.S. at 400. After

observing “two juveniles drinking beer in the

backyard,” the officers “entered the backyard, and

saw—through a screen door and windows—an

altercation taking place in the kitchen of the home.”

Id. at 401. Before entering the home, the officers

witnessed “four adults” struggle “to try to restrain the

juvenile” involved in the altercation—indeed, at one

point, the juvenile “broke free, swung a fist and struck

one of the adults in the face.” Id. Because of this

strike, the adult began to “spit[] blood into a nearby

6

sink.” Id. Ultimately, the officers entered the home

after one adult pressed the juvenile “against a

refrigeration with such force that the refrigerator

began moving across the floor.” Id. Once the occupants

were “aware that the police were on the scene, the

altercation ceased.” Id.

The “officers’ entry [there] was plainly

reasonable under the circumstances.” Id. at 406.

“Nothing in the Fourth Amendment required” the

officers “to wait until another blow rendered someone

‘unconscious’ or ‘semi-conscious’ or worse before

entering.” Id. The officers “had an objectively

reasonable basis for believing both that the injured

adult might need help and that the violence in the

kitchen was just beginning.” Id.

3. Brigham City recognizes that a warrantless

entry is reasonable when there is a “need for official

action and no time to secure a warrant.” Michigan v.

Tyler, 436 U.S. 499, 509 (1978); see also Minnesota v.

Olson, 495 U.S. 91, 100 (1990). Said differently, a

warrantless entry is reasonable when the facts

establish probable cause.

Indeed, when emergencies arise, there is not

enough time for the magistrate’s deliberate and

impartial fact checking. “People could well die in

emergencies if police tried to act with the calm

deliberation associated with the judicial process.”

Wayne v. United States, 318 F.2d 205, 212 (D.C. Cir.

1963) (Burger, J.).

But there is always time to develop probable

cause. That is because the warrant does not establish

probable cause—it verifies it. The warrant

7

requirement does not deny “law enforcement the

support of the usual inferences which reasonable men

draw from evidence.” Johnson v. United States, 333

U.S. 10, 13–14 (1948). Rather, the Fourth

Amendment’s protection demands that “those

inferences be drawn by a neutral and detached

magistrate instead of being judged by the officer

engaged in the often competitive enterprise of

ferreting out crime.” Id. at 14. Thus, the warrant

reflects the Constitution’s requirement “that the

deliberate, impartial judgment of a judicial officer be

interposed between the citizen and the police.” Katz v.

United States, 389 U.S. 347, 357 (1967). Or put

differently, the warrant requirement ensures that a

future entry is, indeed, supported by probable cause.

Cf. Wyoming v. Houghton, 526 U.S. 295, 300 (1999)

(equating the Framers understanding as “reasonable”

with a finding of “probable cause”). The warrant is

not, itself, probable cause.

So the “core question” when evaluating

whether a “warrantless entry” is based on “exigent

circumstances” is “whether the facts, as they

appeared at the moment of entry, would lead a

reasonable, experienced officer, to believe that there

was an urgent need to render aid.” Chamberlain v.

City of White Plains, 960 F.3d 100, 106 (2d Cir. 2020)

(internal citations and quotations omitted). And the

entry is “reasonable” where “law enforcement has

probable cause to believe that a person is ‘seriously

injured or threatened with such injury.’” Id. at 105

(quoting Brigham City, 547 U.S. at 403)). “The mere

possibility of danger is insufficient.” Id. (internal

quotation marks and citation omitted).

8

II.

Reasonable suspicion applies in the

context of street policing, not home

entries.

1. Time and again, this Court has rejected

arguments that permit government intrusions into

the home based on anything less than probable cause.

Start with Tyler. 436 U.S. 499 (1978). There, the

Court rejected Michigan’s argument “that an entry to

investigate the cause of a recent fire is outside” of the

Fourth Amendment’s protection. Id. at 505. Probable

cause is necessary even if “the official conducting the

search wears the uniform of a firefighter rather than

a policeman, or because his purpose is to ascertain the

cause of a fire rather than to look for a crime,” the

Court held. Id. at 406.

Next consider Mincey. 437 U.S. 385 (1978). While

recognizing “that a possible homicide presents an

emergency situation demanding immediate action,”

the Court rebuked Arizona’s attempt to create a

“generic exception” permitting a warrantless entry

whenever a home doubled as a “homicide scene.” Id.

at 391, 392. That “very argument” was already

“rejected when it was advanced to support the

warrantless search of a dwelling where a search

occurred as ‘incident’ to the arrest of its occupant.” Id.

at 391 (citing Chimel v. California, 395 U.S. 752, 766

n.12 (1969)).

Collins is a more recent example. 584 U.S. 586

(2018). In that case, Virginia sought to expand “the

scope of the automobile exception” such that an officer

would have “the right to enter a home or its curtilage

to access a vehicle without a warrant.” Id. at 595. Yet

again, no luck: “Expanding the scope of the

9

automobile exception in this way would both

undervalue the core Fourth Amendment protection

afforded to the home and its curtilage and untether

the automobile exception from the justifications

underlying it.” Id. Collins further grounds its

reasoning in additional decisions in which the Court

“declined to expand the scope of other exceptions to

the warrant requirement to permit warrantless entry

into the home.” Id. (citing Horton v. California, 496

U.S. 128, 136–37 (1990) (declining to extend the plain

view doctrine), G.M. Leasing Corp. v. United States,

429 U.S. 338, 354 (1977) (same), Soldal v. Cook

County, 506 U.S. 56, 66 (1992) (same)).

2. Montana’s attempt to weaken the Fourth

Amendment’s protections goes even further than the

myriad other attempts that have failed. In its BIO,

Montana appears to concede that a warrantless entry

into the home requires probable cause because, in its

view, every circuit, effectively, applies a probable

cause standard. See Brief in Opposition at 16–20; but

see Hill v. Walsh, 884 F.3d 16, 23 (1st Cir. 2018) (“[W]e

hold that the government need not show probable

cause.”). Yet still, Montana maintains that the

decision below—which concededly did not apply a

probable cause standard—correctly held that officers

acting in a “caretaker’s capacity” with “reasonable”

grounds for suspicion may make a warrantless home

entry “that would otherwise be forbidden for lack of

criminal activity and probable cause.” Pet. App. 15a.

Montana is wrong twice over.

a. There is a world of difference between probable

cause—which requires a reasonable belief—and

reasonable suspicion—which merely requires a

reasonable possibility. Ornelas is instructive:

10

Reasonable suspicion is “a particularized and

objective basis for suspecting the person stopped of

criminal activity.” 517 U.S. 690, 696 (1996) (citing

United States v. Cortez, 449 U.S. 411, 417–18 (1981)).

This is a “less demanding standard than probable

cause and requires a showing considerably less than

preponderance of the evidence.” Illinois v. Wardlow,

528 U.S. 119, 123 (2000). But probable cause, Ornelas

continues, exists “where the known facts and

circumstances are sufficient to warrant a man of

reasonable prudence in the belief that contraband or

evidence of the crime will be found.” 517 U.S. at 696.

“Of course, the specific content and incidents of

[the Fourth Amendment] right must be shaped by the

context in which it is asserted.” Terry v. Ohio, 392 U.S.

1, 9 (1968). The doctrinal contexts and applications

between probable cause and reasonable suspicion are

even wider. Probable cause, as explained, is grounded

in the Fourth Amendment’s staunch protections of the

home. But reasonable suspicion arises from street

policing—a context that involves far different

historical and material circumstances than one’s

home.

True, the exigent circumstances exception and

Terry share the understanding that “swift action” “as

a practical matter” cannot be “subjected to the

warrant procedure.” Terry, 392 U.S. at 20. So the

conduct involved in these scenarios “must be tested by

the Fourth Amendment’s general proscription against

unreasonable searches and seizures.” Id. But that is

where the similarities end.

Terry, and its reasonable suspicion progeny,

recognize that police have a general right to “approach

a person for the purposes of investigating possibly

11

criminal behavior even though there is no probable

cause to make an arrest.” Id. at 22. Likewise, the

Fourth Amendment incorporates “the ancient

common-law rule that a peace officer [is] permitted to

arrest without a warrant for a misdemeanor or felony

committed in his presence as well as for a felony not

committed in his presence if there was reasonable

ground for making the arrest.” United States v.

Watson, 423 U.S. 411, 418 (1976). And governmental

interests are weighed only against the Fourth

Amendment’s protections of the “person.” Terry, 392

U.S. at 24–25.

But the government has no general interest in

entering a person’s home: “when it comes to the

Fourth Amendment, the home is first among equals.”

Florida v. Jardines, 569 U.S. 1, 6 (2013). Police do not

enjoy a general right to enter homes based on mere

suspicion of criminal behavior. Payton, 445 U.S. at

590. Nor is there a general right to arrest a person in

their home without a warrant absent exigent

circumstances. Id. “At the Amendment’s very core

stands the right of a man to retreat into his home and

there be free from unreasonable government

intrusion.” Jardines, 569 U.S. at 6. “A sane, decent

civilized society must provide some such oasis, some

shelter from public scrutiny, some insulated

enclosure, some enclave, some inviolate place which is

a man’s castle.” Silverman v. United States, 365 U.S.

505, 511 n.4 (1961).

b. The decision below is wrong. At the crux of the

Montana Supreme Court’s reasoning is the erroneous

conclusion that “[w]hen a warrantless entry is wholly

divorced from a criminal investigation and is

otherwise reasonable … the probable cause element is

12

superfluous and should not impede an officer’s duty to

ensure the wellbeing of a citizen in imminent peril.”

Pet.App.14a.

Tyler rejects this rule. Whether an entry is

divorced from a criminal investigation is “irrelevant

to the question whether the inspection is reasonable

within the Fourth Amendment.” Tyler, 436 U.S. at

505. And as explained, under the emergency aid

exception, a warrantless home entry is reasonable

only if there is probable cause of imminent danger. To

characterize the probable cause inquiry as

superfluous merely begs the relevant question: What

is

the

government’s

burden

to

establish

“reasonableness”?

And there’s the rub. Under the Montana Supreme

Court’s decision, where there are “objective, specific,

and articulable facts from which an experienced

officer would suspect that a citizen is in need of help,”

the

warrantless

intrusion

is

“reasonable.”

Pet.App.16a. But this confirms that the Montana

Supreme Court is applying a standard that applies

only in the context of street policing—it cannot be

extended to evaluating warrantless home entries.

III.

A

reasonable

suspicion

standard

interferes with the Second Amendment’s

right to bear arms in the home.

1. The Second and Fourth Amendments are

closely linked. See District of Columbia v. Heller, 554

U.S. 570, 579 (2008) (recognizing that the First,

Second, and Fourth Amendments uniquely speak to a

“right of the people”). As explained, the Fourth

Amendment’s fierce protection of the home reflects

13

the general principle that the home “is a man’s castle.”

Silverman, 365 U.S. at 511 n.4; see also Randolph, 547

U.S. at 115. This principle likewise underlies “the

inherent right of self-defense” that is “central to the

Second Amendment.” Heller, 554 U.S. at 628. Indeed,

the “right to bear arms” in the “home, where the need

for defense of self, family, and property is most acute”

is at its height. Id. at 628–29. And this right, Heller

made clear, “is deeply rooted in this Nation’s history

and tradition.” McDonald v. City of Chicago, 561 U.S.

742, 768 (2010).

Even though the Second and Fourth Amendments

share an underlying principle—the home is a safe

haven, and people have a right to protect it as such—

the presence of a gun in the home is often weaponized

to justify a warrantless government entry.

This case illustrates that problem. When the

police went to William Case’s home to ensure his wellbeing, Mr. Case was not suspected of any criminal

activity. See Pet.App.3a. Naturally, he did not want

an officer in his home. Nor did the police have a right

to enter his home. Yet still, the police intruded with

“long barrel guns” because they anticipated a

“dangerous situation[].” Pet.App.5a.

The result of the police’s warrantless entry is

nothing short of a tragedy that turns both the Second

and Fourth Amendments on their heads. The police

came to Mr. Case’s home to protect him. After they

arrived, the police shot Mr. Case because he was seen

as dangerous. The basis of the perceived danger? The

well-known fact that Mr. Case exercised his Second

Amendment right to possess a gun in his home. These

facts are not an outlier.

14

Matthew Corrigan, a “U.S. Army veteran and

reservist with no known criminal record,” was

similarly subjected to a similar warrantless entry into

his home predicated on the fear that he was suicidal

and kept a gun in his home. Corrigan v. District of

Columbia, 841 F.3d 1022, 1025, 1028 (D.C. Cir. 2016).

In this case, the police entered Mr. Corrigan’s home a

little after 4:00 a.m., but before entering his home, an

officer stated: “I don’t have time to play this

constitutional bull****. We’re going to break down

your door.” Id. The police made good on that promise.

The warrantless entry triggered Mr. Corrigan’s PTSD

and resulted in a stay in his hospitalization. Id. at

1027.

Kenneth Chamberlain, Sr.’s story is even more

harrowing. See Chamberlain, 960 F.3d 100. Mr.

Chamberlain was a “U.S. Marine veteran,” who

accidentally “activated an emergency medical-alert

system.” Id. The police forcibly entered his home

“heavily armed,” wearing “tactical gear,” and without

a warrant. Id. at 101. This confrontation triggered Mr.

Chamberlain’s PTSD and, after seeing the officers’

guns, retrieved a “knife” and thrusted it “through the

partial opening” in an otherwise closed door to protect

himself. Id. at 103. After finally gaining entry into Mr.

Chamberlain’s home, the officers “tased” and “fired

two shots at him with a handgun. One of those bullets

passed through Chamberlain’s lungs and ribs and

severed his spine, killing him.” Id. at 104.

2. Mr. Case’s facts are problematic in another

respect. Though he was never suspected of any

wrongdoing, the warrantless entry into his home led

Montana to convict him of assault. The basis of this

conviction? Mr. Case’s gun possession caused a

15

reasonable apprehension of serious bodily injury.

Pet.App.6a.

To be sure, whenever a person wields a gun in

another’s direction, fear of bodily injury is reasonable.

But at the same time, it is reasonable to possess a gun

in one’s home for fear of trespassers. Indeed, these

facts present another Second Amendment issue:

Warrantless home entries, in response to purported

emergencies, may give rise to an indictment and

conviction under 18 U.S.C. § 922(g)(1)—the felon in

possession statute. See, e.g., United States v.

Quarterman, 877 F.3d 794 (8th Cir. 2017); United

States v. Najar, 451 F.3d 710 (10th Cir. 2006); cf.

United States v. Snipe, 515 F.3d 947 (9th Cir. 2008).2

Section 922(g)(1)’s categorical ban disarming all

people with a felony conviction—no matter the

underlying crime—is unconstitutional. See Kanter v.

Barr, 919 F.3d 437, 458 (7th Cir. 2019) (Barrett, J.,

dissenting). Any regulation of a Second Amendment

right must be “consistent with the principles that

under pin our regulatory tradition. A court must

ascertain whether the new law is ‘relevantly similar’

to laws that our tradition is understood to permit,

‘applying faithfully the balance struck by the founding

generation to modern circumstances.” United States v.

Rahimi, 602 U.S. 680, 692 (2024) (quoting N.Y. State

Rifle & Pistol Ass’n v. Bruen, 597 U.S. 1, 29 (2022)).

Though “founding-era legislatures categorically

disarmed groups whom they judged to be a threat to

the public safety,” there is no historical evidence that

2 The circuits are split on whether § 922(g)(1) is constitutional.

See United States v. Duarte, 137 F.4th 743, 747–48 (9th Cir.

2025) (documenting the split).

16

“supports a legislative power to categorically disarm

felons because of their status as felons.” Kanter, 919

F.3d at 458 (Barrett, J., dissenting); see also Range v.

Att’y Gen. of the U.S., 69 F.4th 96, 105 (3d Cir. 2023)

(en banc) (Hardiman, J.).

Permitting warrantless home entries based on

reasonable suspicion of an exigent circumstance

exacerbates the issues that arise from the § 922(g)(1)

circuit split.

Start with the Range facts. Following a

conviction of “making a false statement to obtain food

stamps,” Mr. Range was “sentenced to three years’

probation” and “paid $2,458 in restitution, $288.29 in

costs, and $100 fine.” 69 F.4th at 98. Because of this

conviction, Mr. Range was barred from possessing a

firearm under § 922(g)(1). Even so, his wife “gifted

him a deer-hunting rifle” because she did not know

Mr. Range’s prior conviction forbade gun possession.

Id.

Now pretend that Mr. Range keeps the gun to

protect his family. But see id. (“Range learned he was

barred from buying a firearm … then sold” it.). Next

imagine that Mr. Range lives next door to mischievous

teens. One day, those teens call the police department,

scream “get the cops here now my neighbors are

fighting,” provide an address, and hang up. The police

quickly arrive at the home, knock on the door, and

after Mrs. Range opens the door peer into their home.

On the back wall, the police notice the rifle and,

suspicious of a domestic dispute, “ask about the gun,”

“enter[] the apartment,” and “seiz[e] the gun.” United

States v. Quarterman, 877 F.3d 794, 796 (8th Cir.

2017). “All of this, from knock to seeing the gun,

occurred in about 35 seconds.” Id. at 796–97.

17

Under the reasonable suspicion standard, the

police’s warrantless entry is just fine. And, if that

were not enough, the forced entry would then evolve

into a criminal indictment and conviction under §

922(g)(1). See United States v. Jackson, 110 F.4th

1120, 1129 (8th Cir. 2024). Two constitutional

violations. One criminal indictment. One conviction.

This hypothetical could easily be someone’s truth

in Montana, where nearly two-thirds of adults keep a

firearm in their home—the highest rate of firearm

ownership in the country.3 These Montanans also live

in the Ninth Circuit where, under the current state of

the law, even those who were convicted of non-violent

felonies are forbidden from possessing a firearm. See

Duarte, 137 F.4th at 748. Are they, or any of the tens

of millions of gun-owning households in the United

States, less deserving of having their own “oasis,” safe

from unwarranted outside intrusion? Silverman, 365

U.S. at 511 n.4.

***

The government has no business in a person’s

home based on reasonable suspicion. As explained,

this lower standard derives from Terry and arises in

the context of street policing. If officers were

empowered to invade homes based on mere suspicion,

innocuous or unsubstantiated situations will quickly

be reframed as emergencies simply because a gun is

in the home.

Mr. Case’s encounter with the police proves that

a reasonable suspicion standard will ruin lives. Mr.

3 See Heather McCracken et al., Gun Ownership in America,

RAND, https://tinyurl.com/RANDGP (2020).

18

Case legally exercised his Second Amendment right in

his home by owning a gun. Despite—or rather because

of—this fact, the police barged into his home based on

the uncorroborated story of his ex-girlfriend. What

happened next would be ironic if it were not tragic:

The police shot Mr. Case twice; but the entire purpose

of their illegal entry was to prevent Mr. Case from

shooting himself. Mr. Case was then charged with,

and convicted of, assault—adding life-altering insults

to his injuries.

The police are not infallible. Neighbors can be

mistaken. See Bailey v. Kennedy, 349 F.3d 731, 740

(4th Cir. 2003). Exes may lie. See Bruce v. Guernsey,

777 F.3d 872, 877 (7th Cir. 2015). The probable cause

standard accounts for these possibilities. In so doing,

it prevents the police from unnecessarily putting

themselves or others at risk. It also prevents any

encroachment on a person’s Second Amendment right

to bear arms in the sanctity of their home—beyond

preventing an otherwise unwarranted violations of

their Fourth Amendment rights.

19

CONCLUSION

For the foregoing reasons, the judgment of the

Montana Supreme Court should be reversed.

August 6, 2025

Respectfully submitted,

DAVID F. NESS

FEDERAL DEFENDERS

OF MONTANA

104 Second Street

South, Ste. 301

Great Falls, MT

59401

KUFERE J. LAING

MARK S. DAVIES

Counsel of Record

WHITE & CASE LLP

701 Thirteenth Street NW

Washington, D.C. 20005

(202) 626-3600

mark.davies@whitecase.com

JAMES P. BUTLER

WHITE & CASE LLP

75 State Street

Boston, MA 02109

Counsel for Amicus Curiae