In the case of Vachon v. New Hampshire in 1973, the United States Supreme Court ruled that a police officer's testimony about an individual's drunkenness was not enough to convict them for public intoxication without additional evidence. The defendant, Robert Vachon, had been arrested and convicted based solely on an officer’s observation of his alleged intoxicated state. However, no field sobriety tests were conducted nor was there any other corroborating evidence presented at trial to support this claim. The Supreme Court overturned Vachon’s conviction stating that due process requires more than just subjective observations by law enforcement officers to establish guilt beyond a reasonable doubt; objective facts or confirmatory tests are necessary as well.

In the dissenting opinion for Vachon v. New Hampshire, it was argued that the majority's decision to overturn a conviction based on an officer's lack of probable cause was misguided. The dissenting justices believed that while the police officer may not have had specific evidence linking Vachon directly to a crime at the time of his arrest, he did possess enough circumstantial information to reasonably suspect him and justify further investigation. They contended that requiring officers to establish probable cause before detaining suspects could hinder effective law enforcement and potentially endanger public safety by allowing potential criminals more freedom until definitive proof is found. Furthermore, they disagreed with the majority's interpretation of Fourth Amendment protections against unreasonable searches and seizures in this context, arguing instead for a more flexible approach which takes into account practical considerations faced by law enforcement officials in their daily duties.