About: Johnson v. United States (1948 Fourth Amendment case)

Johnson v. United States, 333 U.S. 10 (1948), was a significant United States Supreme Court decision addressing search warrants and the Fourth Amendment. In this case, where federal agents had probable cause to search a hotel room but did not obtain a warrant, the Court declared the search was "unreasonable." Johnson is commonly cited for the proposition that the Fourth Amendment creates a "warrant requirement" for searches, and warrantless searches are "per se unreasonable."