Also known as: unreasonable searches and seizures · fourth amendment search · 4th amendment seizure
Written by attorneys · grounded in primary & secondary sources — see below
A constitutional protection that secures persons, houses, papers, and effects against government intrusions lacking probable cause or a warrant. The protection bars searches and seizures that exceed recognized exceptions or lack particularity in their scope. Evidence obtained through such intrusions is subject to exclusion from criminal proceedings.
Transit officers boarded a bus and directed all passengers to set down their bags. A dog alerted on Una Unger's closed backpack. An officer unzipped the pack and examined its contents without consent or judicial authorization. The manual search violated the protection because no probable cause or warrant exception justified opening the container.
Ursula Ung challenged the admission of items seized from her home during a murder investigation. Prosecutors argued that her status as a non-marital child altered the analysis of the search's validity. The protection applies equally to all persons. Any contrary distinction was rejected.
Select any source to read its text and confirm it supports the definition.
Police entered Uma Upadhyay's apartment without a warrant and removed obscene materials. State prosecutors sought to introduce the items at trial. The court suppressed the evidence because the search lacked probable cause and judicial authorization, extending the federal exclusionary rule to state proceedings.
State officials raided Uriah Urban's home and seized contraceptive materials used by a married couple. The couple challenged the seizure as an invasion of protected personal choices. The protection against unreasonable searches reinforced the zone of privacy surrounding intimate decisions.
Federal agents entered Ulysses Usher's apartment without a warrant and searched his belongings for narcotics evidence. Usher sued the agents directly for the violation. The court recognized an implied damages remedy against federal officers who conduct unreasonable searches.
An officer observed Uriel Urban pacing outside a store and suspected he might be casing it for a robbery. The officer patted down Urban's outer clothing and felt a gun. The limited intrusion was upheld because the officer possessed reasonable suspicion that Urban was armed and dangerous.
A dog sniff in a public place may be minimally intrusive, but unzipping and examining the interior of a backpack requires probable cause or a recognized exception. Without a warrant, consent, or exigent circumstances, the manual search violates the protection and the evidence must be suppressed.
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Accessing months of cell-site records constitutes a search because it reveals detailed movement patterns over an extended period. The government must obtain a warrant supported by probable cause rather than a mere subpoena.
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When a private entity acts jointly with federal officers by providing real-time access to location data without judicial process, the conduct can support a claim for violation of the protection. The absence of an express damages statute does not defeat jurisdiction over the constitutional claim.
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A padlocked shed preserves a reasonable expectation of privacy even when the property is subject to a regulatory program. Forced entry without a warrant, consent, or exigency violates the protection despite the regulatory context.
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…terms of the taking of property; the freedom of speech, press, and religion; the right to keep and bear arms; the freedom from unreasonable searches and seizures; and so on. It is a rational continuum which, broadly speaking, includes a freedom from all substantial arbitrary impositions and purposeless restraints . . . and which also recognizes,…