In Coolidge v. New Hampshire, 403 U. S. 443 (1971), Justice Stewart summarized three requirements that the plurality thought must be satisfied for a plain view search or seizure. First, the police must lawfully make an initial intrusion or otherwise be in a position from which they can view a particular area. Second, the officer must discover incriminating evidence 'inadvertently.' Third, it must be 'immediately apparent' to the police that the items they observe may be evidence of a crime, contraband, or otherwise subject to seizure. As another plurality observed in Texas v. Brown, 460 U. S. 730, 460 U. S. 737 (1983), these three requirements have never been expressly adopted by a majority of this Court, but 'as the considered opinion of four Members of this Court [the Coolidge plurality] should obviously be the point of reference for further discussion of the issue.'
The purpose of the 'immediately apparent' requirement is to prevent 'general, exploratory rummaging in a person's belongings.' Coolidge v. New Hampshire, 403 U.S. at 403 U. S. 467. If an officer could indiscriminately search every item in plain view, a search justified by a limited purpose -- such as exigent circumstances ...