Some police actions require advance judicial approval. A warrant is a written court order authorizing law enforcement to take a specified action, such as arresting a person or searching particular premises for particular items.

Arrest and search warrants must rest on probable cause and describe with particularity the person or place to be searched and the items sought. Officers swear out affidavits; judges or magistrates review them before issuance. Exceptions to the warrant requirement exist for exigent circumstances, consent, and certain other recognized categories.

Evidence obtained in violation of warrant rules may be suppressed in criminal prosecutions. Civil claims can also arise from unlawful searches or arrests. The warrant process interposes a neutral official between the state and private privacy or liberty interests.

• Court order authorizing specific police action
• Requires probable cause and particularity
• Applies to arrests and searches among other acts
• Subject to recognized exceptions and exclusionary remedies