Carroll v. United States 267 U.S. 132 (1925)
CARROLL v. UNITED STATES 267 U.S. 132 (1925)
In Carroll the Supreme Court held that an officer can stop and search an automobile without a warrant if there is probable cause to believe the vehicle contains contraband.
The Court noted that national legislation had routinely authorized warrantless searches of vessels suspected of carrying goods on which duty had been evaded. The analogy was shaky; Congress's complete control over international boundaries would justify searching any imports even without probable cause. The Court also approved this warrantless search on a dubious interpretation of the National Prohibition Act. But the Court had independent grounds beyond history and congressional intent for its decision: the search was justified as an implied exception to the fourth amendment's warrant requirement, because the vehicle might be driven away before a warrant could be obtained. Given these exigent circumstances, probable cause rather than a warrant satisfied the constitutional test of reasonableness. Indeed, legislative approval was not considered in the later automobile search cases.
Jacob W. Landynski