Fourth Amendment

The constitutional protection against unreasonable searches and seizures, requiring warrants based on probable cause

Overview

The Fourth Amendment grew out of colonial anger at general warrants and writs of assistance that let British officials search homes and ships at will, a grievance James Otis argued against in Boston in 1761. Ratified in 1791, it protects the right of the people to be secure in their persons, houses, papers, and effects, and requires warrants to be supported by probable cause and to describe particularly the place to be searched. The Supreme Court created the exclusionary rule for federal cases in 1914 and extended it to the states in Mapp v. Ohio in 1961. Katz v. United States recast the amendment around reasonable expectations of privacy, now tested by digital surveillance.