How is a 'search' legally defined?

A 'search' is legally defined as a government intrusion upon an individual's reasonable expectation of privacy. This definition encompasses the principle that individuals have a certain level of privacy in places they consider private, such as their homes, vehicles, or personal belongings. For a search to be deemed reasonable under the Fourth Amendment, law enforcement usually must have probable cause, which is the basis for obtaining a search warrant or conducting a lawful search.

This understanding is crucial because it establishes the boundary between an individual's rights and the powers of the government. When law enforcement conducts an action that violates this reasonable expectation of privacy without proper justification, it could be deemed unconstitutional, leading to the exclusion of any evidence obtained as a result.

The other options do not capture the legal definition of a search accurately. A casual examination of a public place does not involve an intrusion upon privacy since public areas are not generally subject to reasonable expectations of privacy. An individual's right to refuse access relates to consent rather than defining what constitutes a search. A search executed without probable cause would suggest an unlawful action rather than providing a clear definition of a search itself.