Understanding the Fourth Amendment: Search and Seizure

The Fourth Amendment

The Fourth Amendment to the United States Constitution protects individuals from unreasonable searches and seizures by the government.

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The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Key Principles

Probable Cause: Law enforcement must have probable cause to obtain a search warrant

Warrant Requirement: Generally, police need a warrant to conduct a search

Exclusionary Rule: Evidence obtained through illegal searches cannot be used in court (Mapp v. Ohio, 1961)

Exceptions to the Warrant Requirement

Consent: If you voluntarily agree to a search

Plain View: If evidence is visible without searching

Search Incident to Arrest: Officers can search you when making a lawful arrest

Exigent Circumstances: Emergency situations where evidence may be destroyed or someone is in danger

Automobile Exception: Vehicles can be searched with probable cause but without a warrant (Carroll v. United States)

Stop and Frisk: Brief pat-down for weapons during a lawful stop (Terry v. Ohio, 1968)

Border Searches: Reduced expectation of privacy at international borders

Digital Privacy

The Supreme Court has expanded Fourth Amendment protections to digital data:

Police need a warrant to search your cell phone (Riley v. California, 2014)

Police need a warrant to access cell-site location information (Carpenter v. United States, 2018)