The Fourth Amendment is a hard check on police power. This means police need a good reason before they can arrest someone or look through his or her things.Everyone has a constitutional right to be free from unreasonable searches and seizures; the Fourth Amendment of the United States Constitution guarantees that. In San Antonio and all of Texas, a police officer can enter your home or dwelling with no warrant if they have something called "probable cause." The Fourth Amendment prohibits stopfirst, justifylater policing. The Fourth Amendment requires police to have a certain amount of proof before pulling someone over or arresting them. The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated. Officers exercise discretion in the use of their authority to arrest without a warrant. Under the 4th Amendment to the Constitution, Americans have a right to be free from illegal searches and seizures. Consistent with other matters of law enforcement, the appropriate standard should be one of a "reasonable police officer.