Whren v. United States

While the petitioners did not contend that they had not violated the traffic laws of the District of Columbia, they did maintain that the arcane nature of traffic laws rendered nearly all motorists guilty of repeated infractions, and that in this case police officers had used a minor traffic violation as a pretext to conduct a visual search of the vehicle. Whren and Brown also maintained that the case represented an instance of selective enforcement of the law based on race, contending that their traffic violation might have gone unnoticed if they had not "fit the profile" for drug dealers in the area in which they were stopped. Although the Court found some merit in this last argument, it chose not to consider whether or not the search represented a selective enforcement based on race, holding that this was more properly a Fourteenth Amendment question of Equal Protection and not germane to the petitioners' Fourth Amendment case. The Court thus implied that this latter argument may have been more efficacious for the petitioners. However, the Court was not as sympathetic to the Fourth Amendment case the petitioners advanced, as it upheld the decisions of the district court and court of appeals by a unanimous vote.

Writing for the Court, Justice Scalia agreed with the court of appeals that when police officers observe a traffic violation, they automatically have probable cause to stop the offending vehicle and to issue a citation or a warning to its driver. With probable cause thus established, any incriminating evidence of the traffic violation or any other criminal activity found by an officer in plain view within the stopped vehicle could legally be seized and used as evidence in court. Scalia also noted the possible validity of the petitioners' Fourteenth Amendment argument, however. He thus proposed that, to avoid selective enforcement based on race, the standard for determining reasonableness of traffic stops be amended from automatic probable cause created by any minor infraction to a test of whether any officer, acting reasonably, would have made the same stop.

The Court also rejected the petitioners' argument that traffic stops used as a pretext for obtaining other evidence should be abolished, noting that such pretext would be impossible to ascertain. In the final analysis the Court ruled that as long as a traffic stop was made following an actual traffic infraction it was reasonable by definition.