Fourth Amendment

What It Is

The Fourth Amendment to the U.S. Constitution protects against “unreasonable searches and seizures” by the government. It’s the constitutional foundation for the most common § 1983 claims against police officers:

• Unlawful arrest (seizure without probable cause)
• Excessive force (unreasonable seizure)
• Illegal search (search without warrant or exception)
• False imprisonment (continued detention without justification)

Fourth Amendment claims use the objective reasonableness standard — you don’t need to prove the officer intended to violate your rights, only that their conduct was unreasonable under the circumstances. This makes Fourth Amendment claims the most accessible for pro se plaintiffs.

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.

Seizure vs. Search

A seizure of a person occurs when an officer restrains your freedom of movement through physical force or show of authority. An arrest is a seizure. A traffic stop is a seizure. Being tackled is a seizure.

A search occurs when the government intrudes on a reasonable expectation of privacy. Searching your car, your phone, your home, your pockets.

Both require reasonableness. What’s “reasonable” depends on the specific circumstances.

The Reasonableness Standard

The Fourth Amendment doesn’t ban all searches and seizures — just unreasonable ones. This gives courts enormous discretion. The key question is: Was the government’s action reasonable under the totality of the circumstances?

For arrests: Was there probable cause? For force: Was it objectively reasonable under the Graham factors? For searches: Was there a warrant, or did an exception apply?

Why It Matters for § 1983

The Fourth Amendment generates more § 1983 claims than any other constitutional provision. If police arrested you without probable cause, used excessive force, or searched you illegally, your claim lives under the Fourth Amendment.

Key Cases

• Graham v. Connor, 490 U.S. 386 (1989) — All excessive force claims against officers analyzed under Fourth Amendment
• Tennessee v. Garner, 471 U.S. 1 (1985) — Deadly force limits
• Terry v. Ohio, 392 U.S. 1 (1968) — Stop and frisk: brief seizure requires reasonable suspicion
• Carpenter v. United States, 585 U.S. 296 (2018) — Cell phone location data is a search requiring a warrant