Carroll v. United States
Significance: The Supreme Court held that the Fourth Amendment permits the police to stop and search a vehicle without a warrant when there is probable cause that it contains illegal contraband.
Based on a combination of circumstances, federal agents had reason to think that George Carroll was illegally transporting liquor in his automobile. Following a chase, the agents searched his automobile without a warrant and found bottles of liquor concealed in the back seat. After Carroll's conviction, his lawyers argued that the evidence should have been excluded from his trial because it violated the requirements of the Fourth Amendment. By a 6-2 margin, the Supreme Court rejected the claim. Speaking for the majority, Chief Justice William H. Taft wrote that the U.S. legal tradition had long accepted a distinction between stationary buildings and means of transportation such as boats or automobiles, in which mobility often made it impractical for the police to secure a warrant. At the same time, Taft insisted that the Fourth Amendment prohibited all “unreasonable searches and seizures.” Trying to reconcile these two considerations, he wrote that the police must not stop and search highway travelers unless there is probable cause that the vehicles are carrying contraband. Carroll's so-called “automobile exception” is well established. Since the 1970's, however, the Court had to decide many difficult questions about the implications and limits of the decision. In California v. Carney (1985), for example, the Court held that a motor home, unless situated in a residential location, falls under the Carroll ruling.