In the case of Finch v. United States (1976), the U.S Supreme Court ruled in favor of the government, upholding a conviction for conspiracy to distribute and possess with intent to distribute heroin. The petitioner, Finch, argued that his Fourth Amendment rights were violated when federal agents installed an electronic surveillance device on a public telephone booth he used frequently without obtaining a warrant first. However, the court held that since there was no physical intrusion into any constitutionally protected area by law enforcement officers during their investigation and because they had probable cause to believe criminal activity was taking place at this location based on information from an informant who had been proven reliable in past cases; therefore it did not violate his constitutional rights under Katz v. United States precedent which protects individuals' privacy against unreasonable searches and seizures.

In the dissenting opinion for Finch v. United States, Justice Brennan disagreed with the majority's ruling that a warrantless search of an automobile was justified under the "automobile exception" to the Fourth Amendment. He argued that this exception should only apply when there is probable cause to believe that a vehicle contains evidence of criminal activity and exigent circumstances make obtaining a warrant impracticable. In this case, he believed neither condition was met as police had ample time to secure a warrant before searching Finch's car and they lacked probable cause because their suspicion was based on an anonymous tip which did not provide sufficient detail or demonstrate reliability. Therefore, he concluded that admitting evidence obtained from such searches undermines constitutional protections against unreasonable searches and seizures.