Concept
Hot Pursuit
Exigent circumstances, hot pursuit, and emergency aid
Hot Pursuit
The oldest and most intuitive exigency applies when officers are chasing a suspect. Police in hot pursuit of a fleeing felon may follow the suspect into a dwelling without first obtaining a warrant.1 The reason lies in the time a warrant takes. Getting one means leaving the scene, presenting probable cause to a magistrate, and returning, and a suspect who has just reached a house can use that interval to slip out another door, pick up a weapon, or destroy evidence while officers wait outside. The warrant requirement exists to put a neutral judgment between the police and the home, but it cannot do that job when waiting would defeat the very arrest the warrant would authorize. Hot pursuit therefore excuses the warrant only where delay would undo the arrest, and the excuse lasts only as long as the chase does.
A rule that lets officers cross the threshold on the strength of a chase invites an obvious worry: what keeps a chase from outrunning the warrant requirement? The answer has two parts, and each is the subject of one case taken up below. The first part concerns what officers may do once they are inside. In Warden v. Hayden the Court allowed officers pursuing a fleeing felon to search as broadly as is reasonably necessary to prevent escape or resistance and to ensure their own safety, and to seize the weapons and evidence they encounter along the way.2 The authority to search takes its measure from the danger that justified the entry, which is why it does not grow into a general license to rummage. The second part concerns how far a chase can reach. In United States v. Santana, officers had probable cause to arrest a suspect in a public place, and the suspect retreated into a private dwelling; the Court held that the officers could follow, complete the arrest, and conduct the attendant search without a warrant.3 A suspect cannot defeat a lawful arrest simply by stepping across a threshold.
Both cases involve a suspect whom the police already had probable cause to seize, and in both the exigency exists because the chase is underway. Neither case lets officers enter a home on a hunch that someone inside may be a suspect, since the pursuit exception relieves them of the warrant and leaves the probable cause requirement in place. What the two cases leave open is how much the seriousness of the underlying crime matters, because a chase after a petty offender looks very different from a chase after an armed robber. That question is the subject of the next section, built around Welsh v. Wisconsin, where the minor character of an offense weighed against finding exigency.4 Hayden comes first, because it states what hot pursuit permits once officers are through the door.
Pursuit of an Armed Felon
Warden v. Hayden is the foundation of the hot pursuit exception, and its facts show how short the officers' window was.5 An armed robber entered the Diamond Cab Company in Baltimore, took about $363, and ran. Two cab drivers nearby, drawn by shouts of a holdup, followed him to a house at 2111 Cocoa Lane, and one of them radioed the dispatcher a description of the man and the house he had entered. The dispatcher relayed that report to police who were already heading for the robbery scene.6 By the Court's account, the suspect had gone into the house less than five minutes before the officers reached it.7 Everything the police knew when they arrived therefore came from eyewitnesses who had watched the man run inside.
Within minutes several patrol cars reached the house. An officer knocked and announced the police presence, Mrs. Hayden answered, and the officers told her they believed a robber had entered and asked to search; she offered no objection. The officers spread through the first and second floors and the cellar, found Hayden in an upstairs bedroom feigning sleep, and arrested him once the officers on the lower floors reported that no other man was in the house. While they searched, one officer, drawn to the bathroom by the noise of running water, found a shotgun and a pistol in the flush tank. Another, searching the cellar for the man or the money, found a jacket and trousers of the type the robber was said to have worn in a washing machine. Ammunition and a cap turned up in Hayden's bedroom.8 All of it was used against Hayden at trial, so the question was whether a search made without a warrant could lawfully produce that evidence.
The Court held that both the entry and the search for the robber were valid, because "the exigencies of the situation made that course imperative."9 The officers had been told that an armed robbery had just occurred and that the suspect had entered this house minutes earlier. On those facts the Fourth Amendment did not require them to hold back if waiting would gravely endanger their own lives or the lives of others.10 Two features of the situation made delay dangerous. The man was armed, and the officers could not know who else was in the house. Only a thorough search for persons and weapons could show that Hayden was alone and that the police controlled every weapon that might be used against them or to cover an escape.11 Officers in hot pursuit of a fleeing felon may therefore enter a dwelling without a warrant and search as broadly as reasonably necessary to prevent escape or resistance and to ensure their safety, seizing the weapons and evidence they encounter.12
The exception relaxes the warrant requirement and leaves the other requirements in place. Officers invoking an emergency still need probable cause, and in Hayden they had it from the cab drivers' direct observation that a man matching the description, and armed, had gone into that very house.13 The Court was also careful about the ground it did not rely on. It declined to treat the search as one incident to a lawful arrest, as in Harris v. United States, because Harris was already in custody when the search occurred. In Hayden the seizures came before the arrest or at the same moment as it, as part of an effort to find an armed felon who had run into the house minutes earlier.14 A search incident to arrest assumes an arrest already made. The justification here is the danger of a suspect still at large in the house, which is why the search could begin before any arrest was complete.
That same justification also measures how far the search may go. The permissible scope must be at least as broad as is reasonably necessary to prevent the dangers that the suspect, at large in the house, may resist or escape.15 In practice, officers may look wherever a person could hide or a weapon could be kept, and they may seize the weapons and evidence they come across. The limit runs the other way as well. When Terry v. Ohio later restated the principle, it cited Justice Fortas's concurrence in Hayden for the idea that a search justified by an exigency must be "strictly circumscribed by the exigencies which justify its initiation."16 The exigency is therefore both the license and the ceiling: it explains why officers may enter and why the entry does not become a general search of the home.
Hayden itself shows the scope question arising. It was argued that the officer who found the clothing in the washing machine was looking for neither the suspect nor weapons, since he testified that he was searching for the man or the money. The Court assumed, without deciding, that the exigency supported a warrantless search only for the suspect or his weapons, and it still upheld the seizure. The officer knew the robber was armed and did not yet know that any weapons had been found, so the Court found it fair to infer that he was also looking for weapons.17 Because the clothing was evidence only, the Court also had to reject the old "mere evidence" distinction, which had treated purely evidential items differently from instrumentalities, fruits, and contraband, so the clothing was properly admitted.18
The polarity on the other side of the line turns on whether a chase is really under way. In Hayden the robber was inside a house he had entered minutes earlier, armed, with the officers close behind. Take away the chase and the time pressure disappears.
Students lose this issue when they treat a serious crime alone as an emergency. An armed robbery gives officers probable cause and a reason to hurry, but without a chase there is no minutes-old trail to lose, and the baseline rule applies: officers cannot enter a home without a warrant even to make a routine arrest.19 The exception also ends when its reason ends, which a second invented pair of facts shows.
The same tie to actual pursuit appears in Katz v. United States, where the Court observed that hot pursuit could not justify warrantless electronic surveillance of the kind the agents used, which they began only after an investigation had given them time to seek judicial approval.20 Hayden also involved a felon, and the label matters: in Lange v. California the Court refused to treat every flight of a misdemeanant as an emergency that permits entry into a home.21 The next section turns to United States v. Santana, which asks what happens when the chase begins outside and the suspect steps through the front door of a home.
Retreat Into the Home
In Hayden the chase was already under way when the officers reached the house, because cab drivers had watched the robber run inside. A more common version of the problem begins outside the house. Officers entitled to arrest a suspect in the open catch sight of her at her own front door, and she steps through it. United States v. Santana holds that officers who have probable cause and who set an arrest in motion in a public place may follow the suspect into the dwelling, complete the arrest, and conduct the search that goes with it, all without a warrant.23 The holding rests on two steps, and their order matters. The first is that the doorway where Santana stood counted as a public place. Only after that does her retreat become a question about pursuit.
The facts began with an undercover heroin purchase in Philadelphia. A narcotics officer, Michael Gilletti, arranged to buy heroin from Patricia McCafferty for $115, recorded the serial numbers of the marked bills, and drove her, at her direction, to Santana's residence.24 McCafferty took the money inside, came out with envelopes of white powder, and handed them over, and Gilletti arrested her. Asked where the money was, she answered, “Mom has the money.”25 Other officers drove about two blocks back to the house and found Santana standing in the doorway holding a brown paper bag. They pulled up within fifteen feet, got out of their van shouting “police,” and displayed their identification, and Santana retreated into the vestibule. The officers followed through the open door and caught her there, and as she pulled away the bag tilted and packets of white powder fell to the floor.26 The district court found strong probable cause but suppressed the evidence anyway. It read hot pursuit to mean “a chase in and about public streets,” and it concluded that her retreat from the doorway into the house did not qualify.27
The Supreme Court reversed, and it began by fixing where Santana was standing when the officers first moved to arrest her. The starting point was United States v. Watson, which had held that a warrantless arrest in a public place on probable cause does not violate the Fourth Amendment, so the first question was whether the doorway counted as public.28 The Court conceded that under the common law of property the threshold of a dwelling, like the yard around it, is private ground. It held, however, that the Fourth Amendment cases turn on expectation of privacy, and Santana had none in the doorway, because she was as exposed to public view, speech, hearing, and touch as if she had been standing completely outside her house.29 The reason follows from what the warrant requirement protects. A warrant stands between the police and the privacy of the home, and a person who stands openly at her door, within reach of anyone who walks up, has no privacy at that spot for the warrant to guard. Arresting her there intrudes no more than arresting her on the sidewalk, so officers with probable cause could begin the arrest without a warrant. Students lose this issue when they reason from who owns the doorstep, since the question the Court asked was whether the suspect had any privacy where she stood.
With the arrest lawfully begun in public, the only remaining question was whether stepping inside could stop it, and the Court held that it could not.30 It treated the case as a true hot pursuit governed by Hayden and judged it the easier case: the need to act quickly was greater than in Hayden, and the intrusion was much less.31 The need was greater because the officers were seconds behind a suspect who had just seen them and who was holding a bag, which gave rise to a realistic expectation that any delay would result in destruction of evidence.32 The intrusion was smaller because the officers went no farther than the vestibule, a few feet beyond the spot where she was already exposed, rather than combing a house floor by floor for an armed man.
The district court had also misdefined the chase itself. The Supreme Court corrected it: hot pursuit means some sort of chase, but the chase need not be an extended hue and cry through the streets, and a pursuit that ended almost as soon as it began was no less a hot pursuit.33 Once Santana was arrested, the search incident to that arrest, which produced the drugs and money, was justified on ordinary search-incident principles.34 The Court stated the principle directly: “a suspect may not defeat an arrest which has been set in motion in a public place” by escaping to a private place.35 The rule closes an obvious loophole. If a step across her own threshold ended a lawful public arrest, any suspect within a few feet of home could cancel an arrest by walking inside, and the officers' authority would depend on the suspect's last step rather than on their probable cause.
The steps show which facts carry the result. In Santana the officers had probable cause, the suspect stood open to view at her door, the officers announced themselves and approached, and she retreated only after seeing them. The negative pole removes the public arrest and the chase together.
Let the same suspect stand on his porch, see the officers approach, and step inside, and the facts become those of Santana. The difference lies in what the suspect knows and what the officers have already done. Hot pursuit is justified by the risk that a suspect who knows the police are after him will flee, destroy evidence, or endanger others, and the next section shows that Welsh v. Wisconsin treats those risks as unlikely when the suspect does not know he is being pursued.36
Two further limits keep the case in proportion. Santana involved a heroin sale and a suspect holding a bag of drugs, and the Court later refused to treat every flight by a misdemeanant as an emergency that permits entry into a home; officers must look at the totality of circumstances for imminent harm, a threat to the officer, destruction of evidence, or escape.37 Santana also retreated into her own residence. An arrest warrant alone does not authorize officers to enter a third person's dwelling to look for the person named, absent exigent circumstances, so a pursuit into someone else's house has to be justified by the exigency itself.38
One feature of the facts remains open. The officers learned from McCafferty that Santana held the money, arrested McCafferty, and drove straight back to Santana's house, so the risk that evidence would be destroyed arose only after the police had set events in motion. The dissent pressed the concern that the police themselves may have created the urgency by arresting the intermediary so close to Santana's home.39 Whether an exigency that the police helped bring about can still justify a warrantless entry is the police-created exigency question, which the later section on destruction of evidence takes up through Kentucky v. King.