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certiorari to the supreme court of montana No. 24–624. Argued October 15, 2025—Decided January 14, 2026 In Brigham City v. Stuart, 547 U. S. 398, 400, the Court held that the Fourth Amendment allows police offcers to enter a home without a warrant if they have an “objectively reasonable basis for believing” that someone inside needs emergency assistance. In this case, Montana police offcers responded to the home of petitioner William Case after his ex-girlfriend called 9–1–1 to report that he was threatening suicide and may have shot himself. The offcers knocked on the doors and yelled into an open window, but got no response. They could see an empty handgun holster and something that looked like a suicide note inside, and they ultimately decided to enter the home to render emergency aid. When one offcer approached a bedroom closet in which Case was hiding, Case threw open the closet curtain while holding an object that looked like a gun. Fearing that he was about to be shot, the offcer shot and injured Case. An ambulance was called to take Case to the hospital, and offcers found a handgun next to where Case had stood. Case was charged with assaulting a police offcer. Case moved to suppress all evidence obtained from the home entry, arguing that the police violated the Fourth Amendment by entering without a warrant. The trial court denied the motion, and a jury found Case guilty. A divided Montana Supreme Court upheld the offcers' entry as lawful under Montana's caretaker doctrine, rejecting the contention that an offcer must have probable cause to believe that an occupant needs emergency aid.

Held: Brigham City's objective reasonableness standard for warrantless home entries to render emergency aid applies without further gloss and was satisfed in this case. Pp. 113–119.

(a) “[S]earches and seizures inside a home without a warrant are presumptively unreasonable” under the Fourth Amendment. Brigham City, 547 U. S., at 403. But the “warrant requirement is subject to certain exceptions,” Lange v. California, 594 U. S. 295, 301, including the need to render emergency assistance. The Court frst approved a warrantless home entry to render emergency assistance in Brigham City, holding that offcers may enter when they have “an objectively reasonable basis for believing that an occupant is seriously injured or imminently threatened with such injury.” 547 U. S., at 400. Page Proof Pending Publication The Montana Supreme Court's opinion below strayed from that rule. Most important, the emergency-aid test incorporated in Montana's caretaker doctrine evokes the Fourth Amendment standard of “reasonable suspicion” that applies to relatively non-invasive street stops. But Brigham City adopted a different standard for home entries. Case now urges the Court to understand Brigham City as sounding in probable cause, but the Court declines to put a new probable-cause spin onto the emergency-aid standard. Probable cause is “peculiarly related to criminal investigations,” Treasury Employees v. Von Raab, 489 U. S. 656, 667, and that body of law would ft awkwardly, if at all, in the non-criminal, non-investigatory setting at issue here. Rather than strain to relate probable-cause decisions to emergency-aid situations, Brigham City asked simply whether an offcer had “an objectively reasonable basis for believing” that entry was direly needed to prevent or deal with serious harm. 547 U. S., at 400. Courts should assess the reasonableness of an emergency-aid entry on its own terms, rather than through the lens generally used to consider investigative activity. Pp. 113–117.

(b) The offcers here had an “objectively reasonable basis for believing” that their entry was needed to prevent Case from ending his life. The information the offcers obtained from Case's ex-girlfriend, combined with their observations at the scene, suggested that Case may already have shot himself or would do so absent intervention. The offcers' decision to enter his home to prevent that result was reasonable. Accordingly, the Court affrms the judgment (even though not all the reasoning) of the Montana Supreme Court. Pp. 117–119.

417 Mont. 354, 553 P. 3d 985, affrmed.

J., post, p. 119, and Gorsuch, J., post, p. 124, fled concurring opinions. Fred A. Rowley, Jr., argued the cause for petitioner.

With him on the briefs were Mark R. Yohalem, John B. Ken ney, Eric O. Bravin, Elizabeth Nielson, Christopher R. Bet chie, Nathan D. Ellis, and Kelsey B. Catina.

Christian B. Corrigan, Solicitor General of Montana, argued the cause for respondent. With him on the brief were Austin M. Knudsen, Attorney General of Montana, and Tyler R. Green.

Zoe A. Jacoby argued the cause for the United States as amicus curiae supporting respondent. With her on the brief were Solicitor General Sauer, Acting Assistant Attor ney General Galeotti, Deputy Solicitor General Feigin, and Jenny C. Ellickson.*

Opinion of the Court

Elena Kagan

In Brigham City v. Stuart, 547 U. S. 398, 400 (2006), this Court held that police offcers may enter a home without *Briefs of amici curiae urging reversal were fled for America's Future et al. by William J. Olson and Jeremiah L. Morgan; for the Cato Institute et al. by Matthew P. Cavedon and Brent Skorup; for the Constitutional Accountability Center by Elizabeth B. Wydra, Brianne J. Gorod, and Brian R. Frazelle; for the Montana Association of Criminal Defense Lawyers by Mark S. Davies and David F. Ness; for the National Association of Criminal Defense Lawyers et al. by Daniel B. Levin, Jeffrey L. Fisher, Cecillia D. Wang, Yasmin Cader, and Brandon Buskey; and for the Project for Privacy & Surveillance Accountability et al. by Gene C. Schaerr, Erik S. Jaffe, and Mahesha P. Subbaraman.

Briefs of amici curiae urging affrmance were fled for the State of Michigan et al. by Dana Nessel, Attorney General of Michigan, Ann M. Sherman, Solicitor General, B. Eric Restuccia, Deputy Solicitor General, and Timothy A. Baughman, Special Assistant Attorney General, and by the Attorneys General for their respective jurisdictions as follows: Steve Marshall of Alabama, Stephen J. Cox of Alaska, Kris Mayes of Arizona, Tim Griffn of Arkansas, Patrick J. Griffn of Connecticut, Kathleen Jen nings of Delaware, Brian L. Schwalb of the District of Columbia, James Uthmeier of Florida, Chris Carr of Georgia, Theodore E. Rokita of Indiana, Brenna Bird of Iowa, Kris W. Kobach of Kansas, Russell Coleman of Kentucky, Liz Murrill of Louisiana, Aaron M. Frey of Maine, Anthony G. Brown of Maryland, Lynn Fitch of Mississippi, Catherine L. Hanaway of Missouri, Michael T. Hilgers of Nebraska, Aaron D. Ford of Nevada, Mat thew J. Platkin of New Jersey, Raúl Torrez of New Mexico, Jeff Jackson of North Carolina, Dave Yost of Ohio, Gentner Drummond of Oklahoma, Dan Rayfeld of Oregon, Alan Wilson of South Carolina, Marty J. Jackley of South Dakota, Jonathan Skrmetti of Tennessee, Ken Paxton of Texas, Derek Brown of Utah, Jason S. Miyares of Virginia, Nicholas W. Brown of Washington, and John B. McCuskey of West Virginia; for the Local Government Legal Center et al. by Nadia A. Sarkis and James R. Nik raftar; and for Michael J. Z. Mannheimer by Richard A. Simpson, Michael J. Z. Mannheimer, pro se, F. Andrew Hessick, and Elizabeth Guild Simpson. Briefs of amici curiae were fled for the American Psychiatric Association et al. by Aaron M. Panner; for the LONANG Institute by Kerry Lee Morgan and Randall A. Pentiuk; and for The Rutherford Institute by Michael J. Lockerby and John W. Whitehead.

Page Proof Pending Publication a warrant if they have an “objectively reasonable basis for believing” that someone inside needs emergency assistance. The question presented is whether that standard means that offcers must have “probable cause” for the intrusion, as they typically would when investigating a crime. We hold it does not. The probable-cause requirement is rooted in, and derives its meaning from, the criminal context, and we decline to transplant it to this different one. Brigham City's reasonableness standard means just what it says, with no further gloss. And here it was satisfed because the police had “an objectively reasonable basis for believing” that a homeowner intended to take his own life and, indeed, may already have shot himself.

I

This case began with an alarming phone call—from petitioner William Case to his ex-girlfriend J. H., both residents of a small town in Montana. Case told J. H. on the call that “he was going to kill himself.” App. 67 (testimony of J. H.). Because Case sounded “erratic,” J. H. assumed he had been drinking. Ibid. She tried to talk Case out of committing suicide, but “couldn't reel him back”: With each passing moment, Case “became more methodical about what he was going to do.” Id., at 68. Case said that he was “going to get a note”—presumably meaning a suicide note, for J. H. or others to fnd. Ibid. And then J. H. heard a “clicking” sound, like the “cock[ing of] a gun.” Ibid. J. H. told Case she was going to call the police, but that seemed only to antagonize him: Case replied “he would shoot them all too.” Id., at 69. Finally, J. H. heard “a pop” followed by “nothing”—“just dead air.” Ibid. She “yelled [Case's] name a few times,” but got no response, leading her to think he had “pulled the trigger.” Ibid. So she called 9–1–1 to report the incident and drove as fast as she could to Case's home. Three police offcers, dispatched to do “a welfare check on a suicidal male,” met J. H. outside the house. Id., at 104 (testimony of offcer). They decided the situation was “very Page Proof Pending Publication Page Proof Pending Publication serious,” based both on what J. H. told them about the call and on what they already knew about Case. Id., at 75, 157. The offcers were aware that Case had a history of alcohol abuse and mental-health issues; that he had previously threatened suicide at the school where he worked; and that he had once seemed to attempt “suicide-by-cop,” by confronting the police in a way that was likely to provoke a lethal response. So the three offcers requested that the chief of police come to the scene. While waiting for him, they circled the house looking for signs of injury or danger. They knocked on the doors and yelled into an open window, but got no response. Shining their fashlights inside, they could make out empty beer cans, an empty handgun holster, and a notepad with writing on it, which they took to be the suicide note Case had mentioned to J. H. At that point, however, they saw no sign of Case.

Once the chief came, the offcers conferred and decided to enter the house “to render emergency aid.” Id., at 198. In the best-case scenario, they hoped to “talk [Case] down” and prevent any injury. Id., at 174. But given J. H.'s account, the offcers considered as well another possibility—that Case had already shot himself and might be “in there bleeding.” Id., at 85. At the same time, they worried that if Case remained unharmed, their entry could spark a confrontation. See id., at 174, 192–193. So they equipped themselves with long-barrel guns and a ballistic shield before going in. The offcers entered the house through the front door, about 40 minutes after they frst arrived. They announced themselves loudly, and continued to call out as they walked through the home. Case did not answer; he was hiding in the closet of a bedroom upstairs. When one of the offcers entered that room, Case threw open the closet curtain and appeared from behind it, holding “a black object” which looked like a gun. Id., at 194. Fearing that he was about to be shot, the offcer fred his own rife. The bullet hit Case in the abdomen, and another offcer rushed to administer frst aid. An ambulance was called to take Case to the nearest hospital (where he recovered). Meanwhile, one of the offcers found a handgun in a laundry basket next to the place where Case had stood.

The county attorney charged Case with assaulting a police offcer. Case moved to suppress all evidence obtained as a result of the home entry, arguing that the police had violated the Fourth Amendment by coming into his house without a warrant. The trial court denied the motion on the ground that the police offcers were responding legitimately to an “emergency.” App. to Pet. for Cert. 42a. A Montana jury then found Case guilty of the crime charged.

On appeal, a divided Montana Supreme Court upheld the trial court's ruling that the offcers' entry was lawful. The majority analyzed the issue under its “community caretaker doctrine.” 553 P. 3d 985, 990 (Mont. 2024). It noted that a recent Fourth Amendment decision of this Court, Caniglia v. Strom, 593 U. S. 194, 198 (2021), had rejected a “community caretaking rule” allowing a warrantless home entry even absent a “need to render emergency assistance” to an occupant. But the Montana court thought its community-caretaker doctrine survived that holding because it demanded such an emergency. Under that doctrine, the court explained, police could enter a home to do a “welfare check” only when “objective, specifc and articulable facts” would lead an “experienced offcer [to] suspect” that a person inside “is in need of help or is in peril.” 553 P. 3d, at 990, 991. And the court found that facts meeting that description existed here because of the likelihood of suicide. See id., at 994. The court rejected Case's alternative standard: that a police offcer must have “probable cause to believe” the occupant in need of emergency aid. Id., at 992. The “probable cause” locution, the court suggested, applies only when the police are “engaged in a criminal investigation.” Ibid. The dissenting justices, by contrast, favored the proposed probable- cause rule, which they concluded the offcers here did not Page Proof Pending Publication satisfy. See id., at 996, 998 (opinion of McKinnon, J.). In the dissent's view, the court's different approach resembled the “mere reasonable suspicion” standard applicable to comparatively non-invasive street stops. Id., at 999. That standard, the dissent thought, was too easily met to support a warrantless entry into a home. See id., at 996, 999. We granted certiorari, 605 U. S. 968 (2025), because courts have differed on whether police offcers entering a home to provide emergency aid need “probable cause” to believe that an occupant is in peril.* We conclude that standard, borrowed from the criminal context, is inapt. We instead hold just what we have held before: that the offcers may enter if, but only if, they have an “objectively reasonable basis for believing” that an occupant faces serious danger. Brigham City, 547 U. S., at 400.

II

The Fourth Amendment provides that “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated.” At the “very core” of that guarantee, as this Court has often stated, stands “the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion.” Caniglia, 593 U. S., at 198 (quoting Florida v. Jardines, 569 U. S. 1, 6 (2013)). When the intrusion is into that most private place, “reasonableness” usually means having a warrant. Brigham City, 547 U. S., at 403 (“It is a basic principle of Fourth Amendment law that searches and seizures inside a home without a warrant are presumptively unreasonable”). “But not always: The war*Compare, e. g., Estate of Chamberlain v. White Plains, 960 F. 3d 100, 105 (CA2 2020) (requiring probable cause); United States v. Cooks, 920 F. 3d 735, 742 (CA11 2019) (same); Corrigan v. District of Columbia, 841 F. 3d 1022, 1030 (CADC 2016) (same), with, e. g., Hill v. Walsh, 884 F. 3d 16, 23 (CA1 2018) (not requiring probable cause); United States v. Quarter- man, 877 F. 3d 794, 800 (CA8 2017) (same); United States v. Gambino- Zavala, 539 F. 3d 1221, 1225 (CA10 2008) (same).

Page Proof Pending Publication rant requirement is subject to certain exceptions.” Lange v. California, 594 U. S. 295, 301 (2021). And among those is one pertinent here, involving the need to provide an occupant with emergency aid.

This Court frst approved a warrantless home entry to render emergency assistance in Brigham City. There, police offcers responding to a noise complaint observed through a kitchen window a physical altercation between an adolescent and several adults. As they watched, the teenager punched one of the adults in the face, “sending [him] to the sink spitting blood.” 547 U. S., at 406. The offcers immediately entered the home through a nearby screen door and, announcing their presence, caused the fght to cease. We unanimously approved the warrantless entry as “reasonable under the circumstances.” Ibid. And we explained what made it so: The offcers had “an objectively reasonable basis for believing that an occupant [was] seriously injured or imminently threatened with such injury.” Id., at 400.

Three years later, in Michigan v. Fisher, we reiterated what we had said in Brigham City about the “emergency aid exception.” 558 U. S. 45, 47 (2009) (per curiam). The police in Fisher, also responding to a neighbor's report, found a scene redolent of violence and danger. Three windows were broken, with the glass strewn on the ground outside; blood was smeared on one of the doors, as well as on the smashed- in hood of a pickup truck in the driveway; and, visible through a window, a man inside the house was “screaming and throwing things” at an unseen target. Id.,at48. We held that the offcers' entry in those circumstances was “reasonable under the Fourth Amendment,” just as it had been in Brigham City. 558 U. S., at 48. Using the same standard articulated there, we concluded that the offcers had “an objectively reasonable basis for believing” that an occupant of the home needed immediate aid. Id., at 47 (quoting Brig ham City, 547 U. S., at 406).

Page Proof Pending Publication Finally, in Caniglia, we reaffrmed Brigham City even as we rejected a broader “community caretaking” justifcation for warrantless home entries. The police had gone to Edward Caniglia's home after his wife reported that he was suicidal. Caniglia spoke with the offcers on his front porch and agreed to go to a hospital for psychiatric testing. Then, once he had left, the offcers went inside and took away two handguns he owned. The lower courts approved the entry on the ground that the offcers were performing “community caretaking functions.” 593 U. S., at 196. But we declined to recognize such an “open-ended license” for law enforcement offcers to enter private homes. Id., at 199. Citing Brigham City, we readily acknowledged that offcers may enter a home to “render emergency assistance to an injured occupant or to protect an occupant from imminent injury.” 593 U. S., at 198. But such emergency conditions were indeed necessary and, given the facts, the offcers had never tried to defend their entry on that basis.

The Montana Supreme Court's opinion strayed from the Fourth Amendment rule that trio of decisions sets out. To begin with, the court's use of “community caretaker” doctrine was ill-advised, given that Caniglia contrasted “community caretaking” with “render[ing] emergency assistance” and concluded that the former cannot alone justify a warrantless home entry. Ibid. The Montana court, to be sure, tried to reconcile its approach with Caniglia by depicting its community-caretaker rule as allowing home entries only in emergencies. See 553 P. 3d, at 991. But using terminology that this Court has held misplaced in home-entry cases could serve only to confuse the issue. And yet more fundamental, the emergency-aid test incorporated in Montana's caretaker doctrine is different from the one adopted in Brigham City. As noted above, Montana's test fnds a home entry “reasonable” when an offcer has “specifc and articulable facts” from which to “suspect” that someone needs help. 553 P. 3d, at Page Proof Pending Publication Page Proof Pending Publication 991; see supra, at 112. That test's language, as the dissenting justices noted, evokes the Fourth Amendment standard applying to brief, investigative street stops: “reasonable suspicion” based on “specifc and articulable facts.” United States v. Sokolow, 490 U. S. 1, 7 (1989); Terry v. Ohio, 392 U. S. 1, 21 (1968); 553 P. 3d, at 999 (McKinnon, J.). But Brig ham City did not adopt Terry's reasonable-suspicion standard for home entries, as both the State of Montana and the United States as amicus curiae acknowledge. See Tr. of Oral Arg. 56, 68–69, 80. Rather, Brigham City formulated its own standard for dealing with household emergencies— again, whether an offcer has “an objectively reasonable basis for believing” that an occupant is seriously injured or imminently threatened with such harm. 547 U. S., at 400.

Case, however, wants something more. He recognizes that the Brigham City test applies here, and that it has had but one formulation: In describing and applying that standard, we have never used any different terms. See Brief for Case 24. But still, Case urges us now to understand the Brigham City test as “sound[ing] in probable cause.” Brief for Case 15, 24. What the test really requires, Case contends, is that police offcers “have probable cause to believe [an occupant is] seriously injured or imminently threatened with such injury.” Id., at 2. Case reaches that conclusion based mainly on the Fourth Amendment's recognition of the “sanctity of the home.” Id., at 29. Given that special status, he argues, a home entry's aid-giving, “noninvestigatory purpose” should make no difference: The same probable- cause principles used in deciding whether “criminal activity [is] afoot” should apply as well in “assessing the risk and gravity of an emergency.” Reply Brief 1–2, 8, 16.

We decline Case's invitation to put a new probable-cause spin onto Brigham City. “[T]he probable-cause standard,” this Court has often stated, “is peculiarly related to criminal investigations.” Treasury Employees v. Von Raab, 489 U. S. 656, 667 (1989) (quoting Colorado v. Bertine, 479 U. S. 367, 371 (1987)). The standard's history is “rooted” in the “criminal investigatory context.” O'Connor v. Ortega, 480 U. S. 709, 723 (1987) (plurality opinion); see Henry v. United States, 361 U. S. 98, 100–102 (1959). And the standard has acquired meaning over time by virtue of that context, as judges have assessed, in case after case, the requisite likelihood of fnding criminal contraband or evidence. See, e. g., Illinois v. Gates, 462 U. S. 213, 238–239 (1983). The resulting body of law would ft awkwardly, if at all, in the noncriminal, non-investigatory setting at issue here. So Brig ham City adopted a different approach. Rather than strain to relate probable-cause decisions to emergency-aid situations, we asked simply whether an offcer had “an objectively reasonable basis for believing” that his entry was direly needed to prevent or deal with serious harm. 547 U. S., at 400. In adhering to that question, we respect as ever the “frst among equals” status the Fourth Amendment affords the home. Jardines, 569 U. S., at 6; see Caniglia, 593 U. S., at 198–199. And in that vein, we note that an emergency- aid entry provides no basis to search the premises beyond what is reasonably needed to deal with the emergency while maintaining the offcers' safety. But we assess the reasonableness of that limited entry on its own terms, rather than through the lens generally used to consider investigative activity.

Doing so here yields a ready conclusion: The offcers had, as Brigham City requires, an “objectively reasonable basis for believing” that their intervention was needed to prevent serious harm. As earlier described, the offcers knew frsthand that Case suffered from mental-health and alcohol- abuse problems, and that he had previously talked about committing suicide. See supra, at 111. When they reached Case's house, they learned about J. H. and Case's just concluded phone call—that Case, in an apparently inebriated state, threatened to kill himself, spoke of preparing a suicide note, and quite possibly cocked or even shot a gun before the Page Proof Pending Publication Page Proof Pending Publication line went dead. The concerns that call raised were heightened by what the offcers could see through the windows— empty beer cans, an empty holster, and a notepad—as well as by Case's failure to respond to their urgent knocking. If Case had already shot himself, he could have been severely injured and in need of immediate medical care. And if he had not, the risk of suicide remained acute, given all the facts then known to the offcers. It was thus objectively reasonable for the police to believe that Case needed emergency aid.

Case counters that only the police entry itself created a “likely danger.” Brief for Case 45. His argument turns on the prospect of suicide-by-cop. As noted earlier, Case had once before acted in a way seemingly designed to provoke a lethal police response, as the offcers knew. See supra, at 111. And J. H. told the offcers that Case had threatened to “shoot them all too” if they came to the scene. Supra, at 110. So the “main risk the offcers objectively faced,” Case posits, was that “their very entry would induce” a shootout, leading to a “suicide-by-cop.” Brief for Case 18. And indeed, Case contends, the offcers knew that: Why else would they have “waited roughly 40 minutes after their arrival” before entering his home? Id., at 43. Case concludes that if the offcers had only left well enough alone, nothing would have happened.

But Case much oversimplifes a complex situation. The objective reasonableness of an offcer's conduct under Brig ham City, as in other Fourth Amendment contexts, is evaluated by looking at the “totality of the circumstances.” E. g., Barnes v. Felix, 605 U. S. 73, 80 (2025); Ohio v. Robinette, 519 U. S. 33, 39 (1996). One of those circumstances was no doubt that Case could provoke a confrontation. As noted earlier, that was partly why the offcers called the police chief to the scene and why they carefully considered protective measures—leading to some delay in their entry. See supra, at 111. But there is no basis for thinking that the officers would have gone into Case's home just so he could instigate a gunfght. The circumstances making their entry reasonable, as just stated, were those suggesting that Case may already have shot himself or would do so absent intervention. The statements Case made to J. H. plus the visual evidence corroborating them indicated that Case wanted to end his life. The decision of the offcers to enter his home to prevent that result—even at some signifcant risk to themselves—was (at the least) reasonable. The Fourth Amendment did not require them, as Case now argues, to leave him to his fate.

* * * We repeat today what we have held before: An offcer may enter a home without a warrant if he has “an objectively reasonable basis for believing that an occupant is seriously injured or imminently threatened with such injury.” Brig ham City, 547 U. S., at 400. The offcers' entry satisfed that test. Accordingly, we affrm the judgment (even though not all the reasoning) of the Montana Supreme Court.

It is so ordered.

Concurrence

Sonia Sotomayor

I join the Court's opinion, which holds that police offcers may enter a home without a warrant if they have an “ `objectively reasonable basis for believing' ” that an occupant is seriously injured or imminently threatened with such harm. Ante, at 114, 116, and this page. Although the Montana Supreme Court's opinion appeared, erroneously, to apply a lower standard akin to reasonable suspicion, I agree that the offcers here had an “ `objectively reasonable basis for believing' ” that Case needed emergency assistance because he may have already shot himself or was imminently going to do so. Ante, at 116–118 and this page.

I write separately to underscore the unique considerations that law enforcement and courts should bear in mind when Page Proof Pending Publication assessing whether there is an “objectively reasonable basis to believe” that a person experiencing a mental-health crisis needs law enforcement to “render emergency assistance.” Brigham City v. Stuart, 547 U. S. 398, 403 (2006). As Brig ham City explained, the “ `justifcation for what would be otherwise' ” an illegal warrantless entry of a home in this context is “ `[t]he need to protect or preserve life or avoid serious injury.' ” Ibid. (quoting Mincey v. Arizona, 437 U. S. 385, 392 (1978)). The offcers in Brigham City, for instance, needed to enter the house to break up an ongoing fght to protect a person whom they saw through a window being struck in the face and to prevent further violence. 547 U. S., at 406. When an offcer is called to respond to a person at risk of suicide, however, entering the house may not always be the objectively reasonable course of action to “ `preserve life or avoid serious injury.' ” Id., at 403 (quoting Mincey, 437 U. S., at 392).

In these kinds of circumstances, the presence of law enforcement at times can escalate the situation rather that ameliorate it, putting both the occupant and the offcers in danger. See, e. g., Chamberlain v. White Plains, 960 F. 3d 100, 101–104, 108 (CA2 2020) (offcers repeatedly attempted entry of the home of a person with a known “history of mental illness,” eventually shooting and killing the occupant after he repeatedly said he was “ `okay' ” and offcers saw he did not need medical attention); Bailey v. Kennedy, 349 F. 3d 731, 734–736, 744 (CA4 2003) (offcers attempted to enter house based on a neighbor's report of suicide, eventually kicking and striking occupant to arrest him, despite occupant telling the offcers that he was not suicidal and that they should leave). The risk of escalation is also heightened by the prevalence of frearms in nearly half of American households.1 Police may employ more forceful tactics when they 1In 2025, 42% of Americans reported living in a gun-owning household. Gallup, Guns, https://news.gallup.com/poll/1645/guns.aspx (archived at https://perma.cc/G76N-5T7Z.

Page Proof Pending Publication know a frearm is in the house, and an occupant who is experiencing an acute mental-health crisis may react more unpredictably in response. See, e. g., Corrigan v. District of Co lumbia, 841 F. 3d 1022, 1025–1028 (CADC 2016) (despite occupant voluntarily meeting the police outside and disclaiming any intention to harm himself, the offcers triggered occupant's posttraumatic stress disorder after kicking his door and searching his house, based on report that he was suicidal and owned frearms); Frazier v. Miller, 404 Mont. 1, 484 P. 3d 912, 916 (2021) (occupant initially told police he was “ `fne' ” and to “go away” but drew pistol to his own head when the offcer continued to attempt entry, leading the offcer to draw his gun in response and eventually shoot the occupant).

Studies show that individuals with serious mental-health conditions are disproportionately likely to be injured and seven times more likely to be killed during police interactions compared to the general population.2 One report showed that over a 2-year period, “calls for help resulted in law enforcement offcers shooting and killing the very people they were called on to assist” in 178 cases.3 Another study found that police shooting incidents involving behavioral health concerns (suicidal behavior, substance use, or serious mental illness) were 2.1 times more likely to result in fatal injury than other police shooting incidents.4 Further, individuals with a mental illness were “2.8 times more likely” to 2See H. Jun, J. DeVylder, & L. Fedina, Police Violence Among Adults Diagnosed With Mental Disorders, 45 Health & Soc. Work 81 (May 2020); A. Saleh, P. Applebaum, X. Liu, T. Stroup, & M. Wall, Deaths of People With Mental Illness During Interactions With Law Enforcement, 58 Int'l J. L. & Psychiatry 110, 114 (May-June 2018) (Saleh).

3J. Gerberg & A. Li, When a Call to the Police for Help Turns Deadly, Washington Post, June 22, 2022, https://www.washingtonpost.com/ investigations/interactive/2022/police-shootings-mental-health-calls/. 4J. Ward et al., National Burden of Injury and Deaths From Shootings by Police in the United States, 2015–2020, 4 Am. J. Pub. Health 387, 391– 392 (2024).

Page Proof Pending Publication “be killed in their own homes” compared to those without a mental illness.5 Given these risks, in some circumstances it may be more reasonable for offcers to try different means of de-escalation before entering the home of a person experiencing a mental- health crisis. Offcers could, for example, attempt to speak with the occupant from a distance or over the phone; contact family, friends, or neighbors to help intervene; call in specialized police units, such as negotiators or offcers trained in crisis intervention; 6or otherwise work with mental-health professionals to approach the occupant.7 Offcers called to respond to these kinds of situations should carefully investigate and assess the nature of the potential crisis and determine whether there is an objectively reasonable basis to believe that the occupant needs emergency aid inside before entering without a warrant. Once the decision is made to enter, moreover, the “manner” of the offcers' entry and their subsequent conduct inside must also be “reasonable.” Brig ham City, 547 U. S., at 406.

This case highlights the very complexities that will often attend emergency-aid interventions involving reported mental-health crises. Multiple facts suggested that Case did not need emergency aid but was instead waiting inside for the offcers in order to provoke a confrontation that would result in “suicide-by-cop.”

5Saleh 114.

6See id., at 114–115; Brief for American Psychiatric Association et al. as Amici Curiae 18–25 (describing programs that involve sending teams of specially trained police to respond to calls about mental-health crises). 7Many jurisdictions around the country have introduced programs in which police offcers and mental-health professionals jointly respond to calls about mental-health crises. See Policy Research, Inc. & National League of Cities, A. Krider, R. Huerter, K. Gaherty, & A. Moore, Responding to Individuals in Behavioral Health Crisis Via Co-responder Models (Jan. 2020), https://www.theiacp.org/sites/default/files/ SJCResponding%20to%20Individuals.pdf (archived at https://perma.cc/ LMZ2-FAC9) (describing “co-responder” programs).

Page Proof Pending Publication Case had told his girlfriend, J. H., on the phone that he would “shoot them all” if she called the police to his house. App. 69. Once J. H. arrived at the house, she told the offcers that Case threatened to “shoot it out” with the police. Id., at 70–74. The offcers also knew that in a prior incident in which police were called to respond to a suicide attempt by Case, Case had confronted the police in a way that suggested he was attempting suicide-by-cop. Then, while surveying the house, the offcers discussed how Case had “ `tried suicide by cop before' ” and that it was likely Case was “ `going to pull a gun on us' ” once they “ `go in the house.' ” 417 Mont. 354, 373, 553 P. 3d 985, 998 (2024) (McKinnon, J., dissenting). These facts, taken together, suggested that Case was neither already injured nor about to injure himself, but rather that the primary danger he faced would arise only if the offcers entered his house. In other words, these facts tended to undermine the offcers' basis to believe that he needed emergency assistance inside.

The offcers' warrantless entry ultimately did not violate the Fourth Amendment, however, because there were suffcient facts on the other side of the ledger supporting an objectively reasonable basis to believe that Case had shot himself. Critically, Case had told J. H. he had a “loaded gun” and J. H. heard a “clicking” sound like the “cock[ing]” of “a gun,” a “pop,” and then “just dead air” despite J. H. yelling Case's name multiple times over the phone. App. 68–69; 417 Mont., at 357, 553 P. 3d, at 988. Case also told J. H. that he was “going to get a note” and “kill himself.” App. 67–68. When the offcers arrived, they saw an empty handgun holster and notepad with writing inside Case's house, and Case did not respond when they shouted his name into an open window. Considered together, those facts gave rise to an objectively reasonable basis for the offcers to believe that Case was already injured and in need of emergency medical assistance, and was not necessarily waiting inside for the offcers seeking to provoke an escalation leading to suicidePage Proof Pending Publication Page Proof Pending Publication by-cop. As a result, the offcers did not violate the Fourth Amendment when they entered Case's home.8 That conclusion, on the facts of this case, does not mean it will always be objectively reasonable for offcers responding to a mental-health crisis to make a warrantless entry. A different mix of information might have led to the conclusion that the offcers' entry itself would put the occupant (and offcers) at a greater risk of escalation and serious injury. Because the “objectively reasonable basis” test, as reaffrmed by the Court today, demands careful attention to the case-specifc risks that attend mental-health crises, and requires offcers to act reasonably in response, I join the Court's opinion in full.

Concurrence

Neil M. Gorsuch

Today's case, like another before it, holds that police offcers generally do not violate a person's Fourth Amendment rights when they enter his house without a warrant, but with an “ `objectively reasonable basis' ” for believing someone inside is in physical danger and in need of immediate aid. Ante, at 116 (quoting Brigham City v. Stuart, 547 U. S. 398, 400 (2006)). Importantly, the Court observes, this exception to the warrant requirement permits entry only to the extent reasonably necessary to address the apparent emergency and does not authorize offcers to search a home more broadly. See ante, at 117. With all that, I agree.

But to me, a question lingers: Why? Does the Fourth Amendment tolerate this limited emergency aid exception to the warrant requirement just because fve or more Justices of this Court happen to believe that such entries are “reasonable”? Or is this exception more directly “tied to the law”? Carpenter v. United States, 585 U. S. 296, 397 8Case has not challenged the reasonableness of the offcers' manner of entry or their conduct inside his house after entry. As a result, neither the decision below nor this Court had occasion to consider the reasonableness of that conduct.

(2018) (Gorsuch, J., dissenting). The answer, I believe, is the latter.

From before the founding through the present day, the common law has generally permitted a private citizen to enter another's house and property in order to avert serious physical harm. In those circumstances, and many others, courts have historically held that property rights give way to concern for human safety. See, e. g., 37 Hen. 6, pl. 26; Mouse's Case, 12 Co. Rep. 63, 77 Eng. Rep. 1341 (K. B. 1608); Respublica v. Sparhawk, 1 Dall. 357, 363 (Pa. 1788); Ploof v. Putnam, 81 Vt. 471, 474–475, 71 A. 188, 189 (1908). Courts have long described property-law necessity defenses like these as turning, too, on the adequacy of the defendant's judgment, not a post-hoc assessment of necessity in fact. See, e. g., Mitchell v. Harmony, 13 How. 115, 134–135 (1852); Stone v. Mayor of City of New York, 25 Wend. 157, 176 (N. Y. 1840) (opinion of Verplanck, Sen.); Surocco v. Geary, 3 Cal. 69, 72 (1853).* The common-law emergency rule is now often summarized this way: “One is privileged to enter or remain on land in the possession of another if it is or reasonably appears to be necessary to prevent serious harm to . . . the actor[,] . . . the other[,] or a third person . . . unless the actor knows or has reason to know that the one for whose beneft he enters is unwilling that he shall take such action.” Restatement (Second) of Torts § 197(1) (1963–1964). But, of course, this *Contrary to Mr. Case's argument, King v. Coate, Lofft. 73, 98 Eng. Rep. 539 (K. B. 1772), does not establish that the common law demanded an exacting showing of actual necessity to defeat a claim for trespass. True, Lord Mansfeld explained that any necessity defense in that case would need to “stand the strictest test,” with the “necessity manifestly proved.” Id., at 75, 98 Eng. Rep., at 540. But Coate involved an effort to involuntarily “confn[e] a person in a madhouse” for two months, not a claim over a home entry. Id., at 74, 98 Eng. Rep., at 539. And it is hardly surprising that the common law would demand a good deal more to justify a serious deprivation of liberty than to excuse an invasion of property rights aimed at protecting human safety.

Page Proof Pending Publication Page Proof Pending Publication privilege comes with its logical limitations. So, for example, a private citizen who enters a home to render emergency aid lacks license to do so in a manner “which a reasonable man would not regard as necessary to” address the apparent emergency. Id., § 214, and Comment a; see also id., § 197, Comment a; Des Moines v. Webster, 861 N. W. 2d 878, 883– 885 (Iowa App. 2014); State v. Lukus, 149 Mont. 45, 50–51, 423 P. 2d 49, 52–53 (1967).

Today's decision echoes both the common-law emergency aid rule and its limitations. It does so, to be sure, in the context of a law enforcement offcer, not a private citizen, who sought to enter another's home. But on this point as well the common law has spoken, long providing that offcers generally enjoy the same legal privileges as private citizens. See, e. g., Entick v. Carrington, 19 How. St. Tr. 1029, 1066 (C. P. 1765); 1 J. Chitty, Criminal Law 36 (1819); 2 M. Hale, Historia Placitorum Coronae 91 (1736). And, refecting the common law here again, this Court has held that the Fourth Amendment usually permits offcers lacking a valid warrant to “take actions that any private citizen might do without fear of liability.” Caniglia v. Strom, 593 U. S. 194, 198 (2021) (internal quotation marks omitted). But they normally may do “no more” than that. Kentucky v. King, 563 U. S. 452, 469 (2011); see also Entick, 19 How. St. Tr., at 1066. It should come as no surprise that our decision today might accord with the accumulated learning of the common law—just as it should come as no surprise that our application of the Fourth Amendment ought to be informed by the common law's lessons rather than mere intuition. For a period, to be sure, the miasma created by this Court's Katz era led some to think the scope of the rights guaranteed by the Fourth Amendment depend on nothing more than current judicial instincts about “reasonable expectations of privacy.” See Carpenter, 585 U. S., at 394–395, 405–406 (Gorsuch, J., dissenting). But that confusion cannot last forever, for no one should think the rights of Americans hang on so thin a thread. Instead, and as Justice Story recognized, the Fourth Amendment is made of sturdier stuff, representing “the affrmance of a great constitutional doctrine of the common law.” 3 Commentaries on the Constitution of the United States 748 (1833).

Page Proof Pending Publication Page Proof Pending Publication Reporter’s Note The attached opinion has been revised to refect the usual publication and citation style of the United States Reports. The revised pagination makes available the offcial United States Reports citation in advance of publication. The syllabus has been prepared by the Reporter of Decisions for the convenience of the reader and constitutes no part of the opinion of the Court. A list of counsel who argued or fled briefs in this case, and who were members of the bar of this Court at the time this case was argued, has been inserted following the syllabus. Other revisions may include adjustments to formatting, captions, citation form, and any errant punctuation. The following additional edits were made: p. 123, line 12: “(McKinnon, J., dissenting)” is inserted after “(2024)”