In the 1989 case Smith v. Ohio, the U.S. Supreme Court ruled that a state law allowing police to stop and search individuals without probable cause was unconstitutional. The case involved an individual named Edmund Smith who had been stopped by police while walking down the street in Cleveland, Ohio. Police searched his bag without his consent and found illegal drugs inside it, leading to his arrest for drug possession. However, Smith argued that this violated his Fourth Amendment rights against unreasonable searches and seizures because there was no probable cause for him being stopped or searched in the first place. The Supreme Court agreed with Smith's argument unanimously (9-0), stating that under the Fourth Amendment of Constitution people have a right to be free from unreasonable searches and seizures by government officials unless there is reasonable suspicion of criminal activity based on specific facts known at time of encounter.

In the dissenting opinion for Smith v. Ohio, Justice Blackmun argued that the majority's decision to allow warrantless searches of containers within vehicles during traffic stops was a significant departure from established Fourth Amendment jurisprudence. He contended that this ruling effectively eliminated any expectation of privacy individuals might have in their personal belongings when they are inside an automobile, which he believed contradicted previous court decisions and undermined constitutional protections against unreasonable searches and seizures. Furthermore, Justice Blackmun expressed concern about potential abuses by law enforcement officers who could use this broadened authority to conduct arbitrary or discriminatory searches without probable cause or oversight. He advocated for maintaining stricter standards for vehicle searches to safeguard individual rights and uphold the principles embodied in the Fourth Amendment.