The case of Illinois v. Vitale in 1979 revolved around the issue of whether a state could use evidence obtained through an unlawful search and seizure, specifically when that evidence was used to impeach a defendant's credibility during cross-examination. The Supreme Court ruled in favor of Illinois, stating that while the Fourth Amendment protects against unreasonable searches and seizures, it does not prohibit using unlawfully seized evidence for all purposes. In this particular case, the court held that such evidence could be used to challenge or impeach a defendant's testimony if they chose to testify on their own behalf at trial. This ruling effectively expanded law enforcement’s ability to use illegally obtained evidence in certain situations.

In the dissenting opinion for Illinois v. Vitale, it was argued that the majority's decision to uphold a warrantless search of an automobile trunk based on probable cause alone significantly eroded Fourth Amendment protections against unreasonable searches and seizures. The dissent contended that this ruling effectively eliminated the requirement for law enforcement officers to obtain a warrant before conducting such searches, even when there is ample opportunity to do so without compromising evidence or safety. This interpretation of the "automobile exception" was seen as overly broad and inconsistent with previous rulings which emphasized its narrow scope and necessity-based rationale. It was further noted that allowing such unchecked discretion could lead to abuses of power by police officers, undermining public trust in law enforcement institutions.