The Supreme Court actually issued a good ruling on traffic stops today, and it was unanimous. In BRENDLIN v. CALIFORNIA, Bruce Brendlin, who was convicted of drug possession after a car in which he was a passenger was pulled over by a sheriff's deputy in Yuba County, California, appealed his conviction based on the fact that the traffic stop was later conceded by the state to be illegal.

The state argued that because Brendlin was not the driver of the car, he was not the subject of the illegal stop, and so did not have the right to have the evidence suppressed because of the stop's illegality. In the unanimous opinion written by David Souter, the Court found:

Brendlin was seized because no reasonable person in his position when the car was stopped would have believed himself free to "terminate the encounter" between the police and himself. Bostick, supra, at 436. Any reasonable passenger would have understood the officers to be exercising control to the point that no one in the car was free to depart without police permission.