In Johnson v. United States, the Supreme Court ruled on a case involving the Fourth Amendment's protection against unreasonable searches and seizures. The defendant, Johnson, was convicted of possession of drugs based on evidence obtained during a warrantless search by police officers who smelled burning opium outside her hotel room door. They knocked and demanded entry but when she didn't open immediately they broke in without obtaining a warrant first. The court held that this action violated her Fourth Amendment rights as there were no exigent circumstances justifying an immediate search without a warrant - such as risk to public safety or danger of evidence being destroyed if not acted upon promptly. Therefore, the court reversed her conviction because it was based on illegally obtained evidence.

In the dissenting opinion for Johnson v. United States, Justice Tom C. Clark argued that the majority's decision to suppress evidence obtained through a warrantless search was incorrect and harmful to law enforcement efforts. He believed that officers acted reasonably given their knowledge of illegal activities occurring at the residence in question and imminent destruction of evidence if they waited for a warrant. According to him, this case did not involve an unreasonable search or seizure under Fourth Amendment standards as it fell within exceptions allowing immediate action by police when circumstances demand swift intervention. Furthermore, he contended that excluding such crucial evidence would only serve criminals rather than protect innocent citizens' rights against unlawful intrusions by government officials.