permits a law enforcement officer to stop, detain, and frisk persons who are suspected of criminal activity without first obtaining their consent, even though the officer may lack a warrant to conduct a search or PROBABLE CAUSE to make an arrest. Now known as a Terry stop, this type of police encounter is constitutionally permissible only when an officer can articulate a particularized, objective, and reasonable basis for believing that criminal activity may be afoot or that a given suspect may be armed and dangerous.
The case stemmed from an incident in Cleveland, Ohio, in 1963. Police officer Martin McFadden observed three men engaging in suspicious behavior near the corner of Euclid Avenue and Huron Road. One of the suspects was the defendant, John Terry. Along with code-fendant Richard Chilton and a third man, known only as Katz, Terry was seen pacing in front of a downtown store. Occasionally, the men would pause to confer with each other. More often, McFadden witnessed the men peering into the store's front window. Over a period of ten to twelve minutes, the three men looked into the same store window approximately 24 times.
Based on his training as an officer and 39 years of experience on the police force, including 35 as a detective, McFadden believed that the suspects were "casing" the store for a ROBBERY. Attempting to forestall a possible robbery, McFadden approached the three men and identified himself as a police officer. Not being familiar with any of the suspects, McFadden asked for their names. When the men mumbled unintelligibly in response, McFadden grabbed Terry, quickly patted down his overcoat, and discovered a .38-caliber revolver. After removing the pistol from Terry's coat pocket, McFadden patted down the other two suspects, finding another revolver in Chilton's overcoat. Katz was not armed.
Terry and Chilton were charged with carrying concealed weapons. Prior to trial the two defendants brought a motion to suppress the incriminating evidence seized by McFadden. The defendants argued that the weapons were inadmissible because McFadden had discovered them during an unlawful search. McFadden, the defendants pointed out, possessed neither a valid SEARCH WARRANT authorizing the pat down nor probable cause to...