Constitution

The Fourth Amendment: Searches and Seizures

The Fourth Amendment protects people against unreasonable searches and seizures and requires warrants to rest on probable cause and be particular.

4Conservative Editors · Published November 8, 2026

The text

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.

In plain English

The Amendment has two clauses.

The reasonableness clause. "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated." Four places are named: persons, houses, papers and effects. The standard is reasonableness.

The warrant clause. Warrants may issue only on three conditions: "probable cause," support by "Oath or affirmation," and a "particular" description of the place to be searched and the persons or things to be seized.

The text does not require a warrant for every search. The courts, however, have developed a rule that searches without a warrant are presumptively unreasonable, with several exceptions: searches incident to arrest, consent, exigent circumstances, the automobile exception, and others.

The Amendment limits government agents, not private parties. Its modern uses cover areas the Founders never imagined, from telephones to cell-site data to digital devices.

What the Founders said

The Amendment grew out of the controversy over general warrants and writs of assistance. In Britain, the 1763 case of John Wilkes, whose papers were seized under a general warrant, led to decisions condemning such warrants, and in Massachusetts in 1761 James Otis argued against the writs of assistance that allowed customs officers to search any place at will. John Adams, who watched Otis argue, later said that "then and there the child Independence was born."

The particularity requirement is the answer to those practices. State declarations of rights, including Virginia's and Massachusetts's, had already condemned general warrants.

Anti-Federalists, among them Brutus and the Federal Farmer, complained that the Constitution had no protection against unreasonable searches. Several ratifying conventions asked for one. Madison's draft in 1789 became the Fourth Amendment.

How the courts have read it

  • Boyd v. United States (1886): compelled production of private papers violates the Fourth and Fifth Amendments.
  • Weeks v. United States (1914) and Mapp v. Ohio (1961): illegally seized evidence is excluded from trial, first in federal court and then in state courts.
  • Olmstead v. United States (1928): wiretapping without trespass was not a search; overruled by Katz v. United States (1967), which protected a "reasonable expectation of privacy."
  • Terry v. Ohio (1968): police may stop and frisk on reasonable suspicion.
  • United States v. Jones (2012): attaching a GPS device to a car is a search, reviving the property-based approach.
  • Riley v. California (2014): police generally need a warrant to search a cell phone seized at arrest.
  • Carpenter v. United States (2018): accessing historical cell-site location records is a search requiring a warrant.
  • Utah v. Strieff (2016) and Herring v. United States (2009): limits on the exclusionary rule.

Why it matters now

The Fourth Amendment is the Constitution's answer to the question of how a free people can be policed. Law enforcement is necessary, and a warrant requirement is the Founders' check on it: a neutral magistrate, a showing of probable cause, and a description of the target. Conservatives of every temperament have supported it, whether the concern is a drug raid, a data dragnet, or the surveillance of political opponents.

The newer questions are about data. A phone can hold a person's whole life, and records that once required physical searches are now held by companies. Carpenter and Riley show the Court adapting the Amendment to those facts. A conservative approach asks whether the Founders' protections of "papers and effects" cover digital records, and answers by analogy to what the text guards.

Debates over foreign-intelligence surveillance, geofence warrants, and the purchase of data from brokers will continue. The test the Amendment supplies remains the same: reasonableness, supported where possible by a warrant that names what it seeks.

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