The Fourth Amendment protects against unreasonable searches and seizures. It requires a warrant, based on probable cause, for searches."Reasonable expectation of privacy" is a legal term that refers to the idea that individuals have a right to privacy in certain places or with certain items. Law Scholarship and Publications. Under the exclusionary rule, any evidence obtained in violation of the Fourth Amendment will be excluded from criminal proceedings. To obtain a search warrant or arrest warrant, the law enforcement officer must demonstrate probable cause that a search or seizure is justified. "Under the Fourth and Fourteenth Amendments, an arresting officer may, without a warrant search a person validly arrested. University of Washington - School of Law. Briggs: The Court Offers a Civil Remedy for Fourth Amendment Violations on the Wake of an Eroding Exclusionary Rule, 19 J. Marshall L. The police receive training on search and seizure law.