The 4th Amendment to the United States Constitution ensures that individuals are protected from unreasonable searches and seizures by the government. This amendment was introduced by James Madison in 1789 and ratified in 1791 as part of the Bill of Rights.

Key Provisions

1. Reasonable Expectation of Privacy: The 4th Amendment protects individuals from searches and seizures that violate their reasonable expectation of privacy.
2. Probable Cause: Law enforcement must have probable cause to believe a crime has been committed and evidence of that crime will be found in a specific location or on a specific person before obtaining a warrant.
3. Warrants: Warrants must be issued based on probable cause, supported by oath or affirmation, and must particularly describe the place to be searched and the persons or things to be seized.
4. Exclusionary Rule: Evidence obtained as a result of an unreasonable search or seizure is generally inadmissible in criminal trials.

Exceptions

A. Consent: If an individual gives consent to a search, it may be considered reasonable and lawful.
Incident to a Lawful Arrest: Searches conducted during a lawful arrest may be considered reasonable, even without a warrant.
B. Exigent Circumstances: Searches conducted in emergency situations, such as hot pursuit or to prevent imminent harm, may be considered reasonable and lawful.
C. Plain View: Discovering evidence in plain view, without a warrant or probable cause, may be considered reasonable and lawful.