The Fourth Amendment protects against unreasonable searches and seizures. It requires a warrant, based on probable cause, for searches.The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated. "Under the Fourth and Fourteenth Amendments, an arresting officer may, without a warrant search a person validly arrested. The essence of a provision forbidding the acquisition of evidence in a certain way is that not merely evidence so acquired. Amendment Four to the Constitution was ratified on December 15, 1791. It protects the American people from unreasonable searches and seizures. There's a knock at your door. The Fourth Amendment prohibits the United States government from conducting "unreasonable searches and seizures. The Fourth Amendment is among the first ten amendments that make up "The Bill of Rights".