In Cooper v. California, the U.S. Supreme Court ruled in 1966 that a search and seizure of a vehicle impounded by police was not in violation of the Fourth Amendment's protection against unreasonable searches and seizures. The case arose when Gayle Cooper was arrested for possession of narcotics, which were found during an inventory search of his car after it had been seized under state law related to drug offenses. He argued that this evidence should be suppressed because there wasn't any warrant issued for searching his car while it was impounded. However, the court held that since the vehicle was taken into custody as part of forfeiture proceedings (not merely as evidence), authorities had right to retain, inspect or search it without additional warrants.

In the dissenting opinion for Cooper v. California, Justice Douglas argued that the Fourth Amendment was designed to prevent police from conducting searches and seizures without a warrant or probable cause. He contended that allowing law enforcement to hold onto an individual's property indefinitely until they find evidence of a crime is not in line with this constitutional protection. In his view, once the car had been impounded by authorities following Cooper’s arrest on narcotics charges, there should have been no further intrusion into it unless new circumstances arose justifying another search under established principles of law. The fact that state law allowed such action did not make it constitutionally acceptable because state laws cannot override federal constitutional rights. Therefore, he believed that any evidence obtained through these means should be considered inadmissible in court as it violates individuals' right against unreasonable searches and seizures.