An Overview of the Fourth Amendment of the U.S. Constitution

The Fourth Amendment of the U.S. Constitution protects the homes and property of Americans from unreasonable searches and seizures. It requires a warrant to be issued before a search can be conducted (with some exceptions). Like many of the rights in the Constitution, the Fourth Amendment has its roots in English legal doctrine. The notion that an individual's home is their castle and should be protected from intrusion by authorities was raised as far back as 1604.

The Fourth Amendment was ratified in the United States as a part of the Bill of Rights in 1791. The U.S. Supreme Court ruled in 1949 and further in 1961 that it also applies to state laws.

What is Search and Seizure?

Search and seizure involves law enforcement investigation of property believed to be evidence in a crime. The search is often followed by the taking of evidence into possession. Law enforcement is generally allowed to perform reasonable searches and seizures. This may involve obtaining a search warrant or certain circumstances when a warrant may not be legally required. The Fourth Amendment, however, protects individuals against unreasonable search and seizure.

Warrants and Probable Cause

The Fourth Amendment states that search warrants must be supported by an oath or affirmation and may only be issued based on probable cause. Warrants must also include the location of the place to be searched and a description of the items or individuals being searched.

The probable cause requirement means that law enforcement must know specific facts and circumstances that would cause a reasonable person to think that criminal behavior is afoot. Probable cause in terms of seizure requires that the officer knows certain facts or circumstances that would lead a reasonable person to believe an item was stolen, illegal or evidence to a crime.

The Expectation of Privacy

Individuals are only protected by the Fourth Amendment when they have a reasonable expectation of privacy. This requires that the individual believes they have privacy in a certain location and that society deems that expectation reasonable. For instance, if a person believes they have privacy in a public restroom, society would likely deem that reasonable. Non-transparent purses or bags can also provide a reasonable expectation of privacy.

Those who knowingly reveal private items to the public eye are not protected by the Fourth Amendment. Items in plain view, even when on your personal property, may still be seized without a warrant. An item clearly visible in the back seat of a car, for example, is in plain view and may not require a warrant to seize. Same goes for items visible through a window on a public street. When ruling on the expectation of privacy, courts generally look to a person’s intentions.

Exceptions to the Warrant Requirement

A warrant is not necessary for search and/or seizure in all cases. A search that is incident to a lawful arrest, for example, does not require the prior issuance of a warrant. A warrant is also not required to seize evidence that is in plain view of the law enforcement authorities as long as they are legitimately in a location where the items can be viewed. The consent of a person with authority over the property also removes the need for a warrant. Same goes for when a legitimate traffic stop is made and the officer has probable cause to believe that the vehicle contains contraband or the fruits of a crime.

Fourth Amendment Violations

Criminal defense attorneys may claim that the Fourth Amendment rights of their clients were violated in a number of situations. Many arguments hinge on whether or not an officer legitimately had probable cause. Arguments also look at whether a defendant had an expectation of privacy oif items seized were in plain view. Still other cases focus on the language or validity of search warrants.