Ybarra v. Illinois

The warrant authorized a search of the Aurora Tap Tavern and of Greg, the bartender; it did not authorize a search of Ybarra or the other customers. The supporting affidavit never suggested that tavern patrons were buying drugs, carrying drugs, or otherwise participating in criminal activity. Indeed, the warrant's express authorization to search Greg underscored that the police had identified one person, rather than every person present, as a proper object of the search.

Probable cause to search a person must be particularized to that person. Ybarra's mere proximity to a bartender independently suspected of possessing heroin did not create probable cause to search Ybarra. When officers entered the tavern, they did not know Ybarra, did not see him behave suspiciously, and had no reason to think that he had committed, was committing, or was about to commit an offense.

The Fourth Amendment protects the privacy interests of persons, not simply places. Each customer in the tavern retained an individual constitutional protection against unreasonable search and seizure, separate from the protections belonging to the tavern proprietor and Greg. A valid warrant for the premises therefore did not itself permit officers to invade every patron's privacy.

The Court did not decide whether the Illinois statute was facially invalid in every setting. It held instead that applying the statute to authorize this search, without probable cause or another valid Fourth Amendment justification directed at Ybarra, violated the Fourth and Fourteenth Amendments.

Terry creates a narrow exception to the usual probable-cause requirement: an officer may pat down a person for weapons only when the officer reasonably believes or suspects that the particular person is armed and dangerous. The doctrine permits a limited protective search for weapons, not a generalized search for evidence or a routine frisk of everyone at a location.

Nothing about Ybarra gave the officers reason to suspect that he was armed or dangerous. He had empty hands, made no threatening gestures or suspicious movements, and acted without hostility. The only fact the officer identified was Ybarra's three-quarter-length jacket, ordinary clothing for an Illinois tavern patron in early March.

Because the initial patdown was unconstitutional, the Court did not need to decide whether feeling a cigarette pack containing objects gave the officer probable cause to believe that Ybarra possessed narcotics. The State's effort to justify the later removal of the pack depended on a valid initial frisk, and that prerequisite was absent.

Illinois stressed the strong governmental interest in controlling dangerous drugs and the ease with which narcotics can be concealed or transferred among people. But those considerations did not displace the ordinary requirement of probable cause particularized to the person searched.

The Court relied on the principle of United States v. Di Re: a person's presence in a place or vehicle suspected of containing contraband does not, by itself, strip that person of Fourth Amendment protections. Although Di Re involved a warrantless automobile search and this case involved a premises warrant, both cases reject the idea that the suspected presence of readily concealed contraband automatically justifies searching every nearby person.

Probable cause is the constitutional compromise between effective law enforcement and protection against arbitrary invasions of privacy. The circumstances here did not fit any recognized exception allowing a search on less than probable cause, and the Court declined to create a new exception for people found on small premises being searched for narcotics.