The Fourth Amendment of the U.S. Constitution protects individual privacy interests by preventing unreasonable searches and seizures. An individual’s privacy interests are referred to as a person’s reasonable expectation of privacy. The Fourth Amendment protects this interest by limiting when and how police can conduct a search of a citizen’s house, papers, effects, or physical person.

However, the Fourth Amendment only protects people against "unreasonable" searches. "Reasonable" searches can override a person’s Fourth Amendment privacy concerns. Generally, the police need two things before they can invade a person’s reasonable expectation of privacy:

  • Probable cause
  • A search warrant issued by a judge that specifies the details of the search

Under certain circumstances however, the police can conduct searches without a warrant.

What Is a Reasonable Expectation of Privacy?

The Fourth Amendment only applies to searches that violate a person’s reasonable expectation of privacy. If no reasonable expectation of privacy exists, then the Fourth Amendment cannot protect that search. Courts ask two questions when determining whether a person had a reasonable expectation of privacy:

  • Did the person actually expect some degree of privacy?
  • Is society willing to recognize that person’s expectation of privacy?

What Is a Search Warrant?

A search warrant is an order authorizing police officers to search for specific objects or materials at a specific time and location. Police obtain these warrants by showing a judge that they have probable cause to believe that criminal activity is taking place and that illegal contraband will be found at the place to be searched.

What Is Probable Cause?

The Fourth Amendment does not define probable cause; it is a term developed by judges and lawyers to assist in determining the reasonableness of a search. Probable cause occurs where the facts and circumstances of a situation combined with a police officer’s knowledge and experience lead him to believe that criminal activity is occurring. Thus, probable cause is somewhere above a mere suspicion but less than beyond a reasonable doubt.

Generally, in cases where a police officer seeks a search warrant, and his probable cause is mistaken but made in good faith, the search can still be considered valid and reasonable.

What Can You Do If You Have Been Subject to an Illegal Search and Seizure?

A government lawyer can help you navigate through the complex legal system and restore your privacy rights. If a search is unreasonable, the police cannot use any evidence obtained in the search. Therefore, it is important to discuss the search with a criminal defense lawyer who can evaluate the search procedure.