Back in December, I blogged about the oral argument in Arizona v. Johnson, a Fourth Amendment case on the stop-and-frisk power. As I wrote at the time, "[a]t its broadest level, the case raises the question of whether a police can 'pat down' a suspect for weapons if the office reasonably believes the suspect poses a danger to him but there is no evidence that there is criminal activity afoot."

  This morning the Supreme Court handed down the decision in a unanimous opinion by Justice Ginsburg. The Court limited its opinion to how this power applies in a traffic stop setting. It held first that the Terry v. Ohio power to detain is met in a traffic stop setting "whenever it is lawful for police to detain an automobile and its occupants pending inquiry into a vehicular violation." Second, "To justify a patdown of the driver or a passenger during a traffic stop, however, just as in the case of a pedestrian reasonably suspected of criminal activity, the police must harbor reasonable suspicion that the person subjected to the frisk is armed and dangerous." That is, the police can pat-down the passenger in a lawful traffic stop if the passenger is reasonably suspected of being dangerous regardless of what other crimes are suspected.

  This is a very short opinion, but off the top of my head I think there are some interesting issues going on here. First, there is the question of the constitutional status of traffic stops: Are they essentially Terry stops, or are they just regulatory stops justified by probable cause to believe a traffic violation occurred that don't trigger the Terry rules? This opinion suggests that the Court largely sees traffic stops as largely equivalent to Terry stops. Second, there is the question of when a traffic stop ends: The Court finds "nothing" to lead the passenger to believe the traffic stop had ended, which to my mind suggests that traffic stops are ordinarily going to be considered ongoing until the officer affirmatively indicates that it is over. There's more in there, but I'll put this post up for now and may return to the opinion later today.

  UPDATE: Am I right that under Johnson, an officer who makes a traffic stop now has the clear authority to order all the passengers to remain either in the car or near the car for the duration of the stop? The Court writes: "The temporary seizure of driver and passengers ordinarily continues, and remains reasonable, for the duration of the stop. Normally, the stop ends when the police have no further needto control the scene, and inform the driver and passengers they are free to leave." (emphasis added).