Police in California stopped a car to see if the registration was current, without first developing reasonable suspicion to stop the car. Brendlin was a passenger in the car. The officer effecting the stop recognized him, learned that he was wanted for a parole violation, and arrested him. This led to a search of the car, which led to the discovery of meth paraphernalia, and Brendlin was charged with manufacturing. Brendlin moved to suppress the evidence, saying that the initial stop was invalid. This one went back and forth on each appeal. The government conceded that there wasn't a reason to stop the car, but argued that Brendlin was not seized at the time of the illegal traffic stop, but only when he was actually placed under arrest, and therefore did not have standing to challenge the stop.
The Supreme Court held that the passengers of a car are seized during traffic stops, and therefore they may challenge the validity of the stop.