Constitution
Amendment 4: Searches and Seizures
Text from National Archives. Explanation last updated September 29, 2026. How we check this
Banaka study guide
In plain English
The Fourth Amendment protects people against unreasonable searches and seizures of their persons, houses, papers and effects, and says that warrants may issue only on probable cause, supported by oath or affirmation, and describing the place to be searched and the persons or things to be seized.
It is the constitutional source of much of American criminal procedure and of privacy law. Courts ask two questions: whether a search or seizure occurred, and whether it was reasonable, which usually means it was authorized by a proper warrant or falls within an exception.
The text
As printed by the source cited at the end of this page, with its original spelling, capitalization and punctuation.
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.
Explained section by section
The right to be secure
The amendment opens with a right, not a rule of procedure: “the right of the people to be secure in their persons, houses, papers, and effects”. The listed categories were the things the founders most feared being invaded by general searches under the authority of the Crown.
In Katz v. United States (1967) the Court said the amendment protects people and their reasonable expectations of privacy, not just physical places, which is why it can apply to a phone booth and, later, to electronic data.
“Unreasonable searches and seizures”
The text bans unreasonable searches, not all searches. Courts generally treat a search with a warrant as reasonable, and a warrantless search as presumptively unreasonable unless it falls within an established exception, such as consent, exigent circumstances or a search incident to a lawful arrest.
A “seizure” includes taking a person into custody as well as taking property.
The warrant requirements
The second half sets the conditions for a valid warrant: probable cause, an oath or affirmation, and particularity about what will be searched and seized. Particularity was aimed at “general warrants” that let officials search anywhere for anything.
Context and current status
The amendment reflects colonial anger at general warrants and writs of assistance, which allowed customs officers to search for smuggled goods without naming a place or person. It was ratified on December 15, 1791.
The Supreme Court held in Mapp v. Ohio (1961) that evidence obtained in violation of the amendment generally cannot be used in state criminal trials (the exclusionary rule). Later cases including Riley v. California (2014), which required a warrant to search a cell phone seized during an arrest, and Carpenter v. United States (2018), on historical cell-site location records, apply the text to digital technology. Current textual status: unchanged and in force.
Terms to know
- Probable cause
- A reasonable basis, supported by facts, to believe that a crime has been committed or that evidence will be found in the place to be searched.
- Warrant
- A written order from a judge or magistrate authorizing a search or an arrest.
- Particularity
- The requirement that a warrant name the place to be searched and the things or persons to be seized.
- Exclusionary rule
- The rule that evidence gathered through an unconstitutional search may be barred from trial.
Common misconceptions
“Police always need a warrant to search.”
The text bans unreasonable searches. Courts recognize many exceptions, including consent and emergencies, in which a warrantless search can still be reasonable.
How it connects
Links to related provisions and documents, with the reason each one matters here.
- Amendment 5Grand Juries, Double Jeopardy, Self-Incrimination, Due Process and TakingsThe Fifth Amendment’s protection against self-incrimination and the Fourth Amendment’s limits on evidence-gathering together shape what police and prosecutors may do.
- Amendment 6Criminal Trials: Speedy Trial, Jury, Confrontation and CounselThe Sixth Amendment governs the trial that may follow an arrest and search, guaranteeing notice, counsel and confrontation.
- Amendment 14Citizenship, Due Process and Equal ProtectionThe Fourteenth Amendment is how the Fourth Amendment’s limits came to bind state and local police.
Study check
Check your understanding of the Fourth Amendment
Choose an answer, then check it. Scoring happens in your browser; your answers are not sent anywhere.
Sources and corrections
- Text: National Archives. Checked against the source on September 29, 2026.National Archives transcription of the engrossed Constitution, with original spelling and capitalization. The signature block and the Convention's interlineation note are not reproduced.
- The Bill of Rights: A Transcription — National Archives
- The Interactive Constitution: Fourth Amendment — National Constitution Center
Educational material, not legal advice. Spotted a mistake? Tell us; corrections change this page’s update date.