Three police officers, including Maria Trevizo, were on patrol in Tucson, Arizona, near a neighborhood associated with the Crips gang, when they pulled over a car with a suspended registration. Each officer talked to one of the three occupants. Trevizo spoke with Lemon Johnson, who was wearing clothing consistent with Crips membership. Visible in his jacket pocket was a police scanner, and he said that he had served time in prison for burglary. Trevizo asked him to get out of the car and patted him down “for officer safety.” She found a gun. Johnson was charged in an Arizona state court with illegal possession of a weapon. What standard should apply to an officer’s pat down of a passenger during a traffic stop? Should a search warrant be required? Could a search proceed solely on the basis of probable cause? Would a reasonable suspicion short of probable cause be sufficient?