The Fourth Amendment to the United States Constitution prohibits the federal government from conducting unreasonable searches and seizures. The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated.If courts find a search or seizure is not reasonable and a person's 4th. What Does the Fourth Amendment Mean? The Fourth Amendment's rule against unreasonable search and seizures means that police may not search you or your property unless one of the following is true:. A police officer must fill out an affidavit and present it to a neutral judge or magistrate to obtain a warrant. Probable cause is present when the police officer has a reasonable belief in the guilt of the suspect based on the facts and information prior to the arrest. But in the face of Prohibition, courts began to narrowly read the Fourth Amendment to give federal agents broader authority to search for illegal alcohol. California, 374 U.S. 23 (1963). Read on to find out how this critical law can make a difference in your criminal case.