In the case of Delaware v. Prouse, the U.S. Supreme Court ruled in 1979 that police officers cannot stop vehicles without a reasonable suspicion of an offense being committed by the driver or passengers. The court held that random stops violated the Fourth Amendment's protection against unreasonable searches and seizures. This decision was based on a case where a patrolman had stopped a vehicle driven by William Prouse III to check his license and registration, with no specific reason to suspect any wrongdoing. During this stop, marijuana was found in plain view inside the car leading to Prouse’s arrest for possession of controlled substances. However, due to lack of initial probable cause for stopping him, evidence obtained during this search was deemed unconstitutional and suppressed from trial proceedings.

In the dissenting opinion for Delaware v. Prouse, Justice Rehnquist argued that the majority's decision failed to properly consider the balance between individual rights and public safety. He contended that random stops by police officers can serve as an effective deterrent against drunk driving and other traffic violations, thereby promoting overall road safety. Furthermore, he disagreed with the majority's assertion that these stops constitute a significant intrusion on personal privacy or freedom of movement. Instead, he viewed them as minor inconveniences necessary for maintaining law and order in society. Additionally, Justice Rehnquist expressed concern about limiting police discretion without clear evidence of widespread abuse or discrimination in their practices.