Why the Exception Exists

Why the Exception Exists

The exception makes sense only against the rule it departs from, and that rule comes with an allocation of burden that shapes how every later case is argued. A warrantless search begins as presumptively unreasonable, and the party who wants it excused must carry the load. In Chimel v. California the Court repeated that “the burden is on those seeking [an] exemption [from the requirement] to show the need for it.”¹ The burden sits there because an officer who has just decided to search is poorly placed to judge whether the search was necessary, and the warrant requirement exists to put that judgment in other hands. If the bare fact of an arrest were enough, police could avoid the magistrate in any case where they could make an arrest first. So the prosecution must tie a warrantless search to the specific dangers that justify it, and Chimel borrowed Terry's statement of the limit: the scope of a search must be “strictly tied to and justified by” the circumstances that made its initiation permissible.² Three questions follow from that framing: what the dangers are, what event unlocks them, and how far they reach.

The Two Dangers

Chimel identifies two dangers, and each justifies something different. The first is that the arrestee may seize a weapon and use it to resist arrest or to escape, in which case the officer's safety “might well be endangered, and the arrest itself frustrated.”³ The second is that the arrestee may conceal or destroy evidence, which supports looking for and seizing evidence on the arrestee's person before it disappears.⁴ The weapons concern justifies looking for anything that could hurt the officer or free the arrestee, while the evidence concern justifies looking for items small enough to hide or destroy in a few seconds. Both dangers peak at the moment of arrest, and an officer cannot pause then to find a magistrate. That timing explains why the arrest, rather than the suspected offense, is the source of the authority. As the Court put it in United States v. Robinson, “[t]he danger to the police officer flows from the fact of the arrest, and its attendant proximity, stress, and uncertainty.”⁵

The contrast with a brief weapons frisk on reasonable suspicion shows why two justifications matter. A frisk rests on the weapons danger alone, so the Court has said it is not justified by any need to prevent destruction of evidence and must stay confined to finding guns, knives, clubs, and similar instruments.⁶ A search incident to arrest has both justifications available, which is why it can be more extensive. Chimel's own illustration of the weapons danger makes the point concrete: a gun on a table or in a drawer in front of an arrestee can be as dangerous to the officer as one concealed in the arrestee's clothing.⁷ Officers who lawfully arrest a burglary suspect in a living room may therefore check the tabletop beside the suspect, because a hand could reach it in an instant.

The Custodial Arrest Trigger

The dangers arise from the situation of arrest, so the exception opens only on a lawful custodial arrest, and each adjective does its own work. “Lawful” means constitutionally valid, which in practice means supported by probable cause, and a search incident to an arrest that itself violates the Constitution violates it too. The test is constitutional validity, so an arrest that breaks a state-law rule but rests on probable cause still supports the search, as Virginia v. Moore holds. The arrest must also be grounded in facts other than what the search turns up. In Rawlings v. Kentucky the search came just before the formal arrest and was still treated as incident to it, because the arrest followed quickly and rested on probable cause independent of the search.⁹

“Custodial” means the police actually take the person into custody rather than issuing a citation. In Knowles v. Iowa a driver clocked at 43 in a 25 zone was given a citation and not arrested, and the search that followed was invalid. The reason lies in the dangers themselves: a citation carries less threat to the officer than an arrest does, and the only evidence of the speeding had already been found. Students lose this issue when they assume that a citation is not a custodial arrest yet still treat the stop as enough to justify the search.

Once the trigger is met, the seriousness of the offense does not matter. In Robinson the officer arrested a driver for driving without a license, patted him down, and opened a cigarette package that held heroin, and the Court upheld the search even though the offense of arrest left no evidence to find.¹⁰ The Court reasoned that a custodial arrest based on probable cause is a reasonable intrusion, and that “a search incident to the arrest requires no additional justification.”¹¹ In other words, the dangers are presumed from the fact of a custodial arrest, which is why the next section can treat the search of the person as categorical.

Scope Follows Justification

Because the two dangers are what unlock the search, the search can extend only as far as the dangers do. The causal sentence the reader can reuse is this: where the arrestee has no ability to reach an area, neither danger exists there, and the justification for searching it disappears. Arizona v. Gant describes the Chimel limit in just these terms, as the boundary that keeps the scope of a search incident to arrest commensurate with its purposes of protecting officers and safeguarding evidence the arrestee might conceal or destroy.¹³ If there is no possibility that the arrestee could reach into the area the police want to search, both justifications are absent and the exception does not apply.¹⁴ Chimel drew the line at reach and not at the room: it found no comparable justification for routinely searching any other room, or for going through desk drawers and other closed or concealed areas even within the room of the arrest. Such searches, absent a recognized exception, require a warrant.¹⁵

The reason for tying scope to reach comes from the structure of the rule. The arresting officer decides whether and when to arrest, so a rule that let any arrest open a broader search would hand the officer a way around the warrant requirement. Before Chimel, courts had at times allowed a full warrantless search of the premises merely because the arrest took place there, and the scope of the exception has been debated nearly as long as the exception has existed.¹⁶ Chimel's reach-based boundary gave officers a line they could apply at the scene. Each later rule in this chapter, for the grab area, vehicles, phones, and home sweeps, applies the same reasoning to a new setting.