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 Amendment to the US Constitution, the police are prohibited from conducting a search and seizure without "probable cause."The Fourth Amendment of the United States Constitution protects us all from illegal searches and seizures. The Fourth Amendment to the United States Constitution prohibits the federal government from conducting unreasonable searches and seizures. The Fourth Amendment to the U.S. Constitution generally prevents the government from arresting or searching a person without a warrant. The Fourth Amendment protects us from unreasonable search and seizures of our person, our house, our papers, and our effects. But cracks in the Fourth Amendment have weakened our personal security. Pennsylvania legislators have proposed almost 40 changes to the state constitution. Here's where they are in the legislative process. Amendment Four to the Constitution was ratified on December 15, 1791.