Page:Riley v. California Opinion.djvu/5

 Opinion of the Court II

The Fourth Amendment provides:

As the text makes clear, "the ultimate touchstone of the Fourth Amendment is 'reasonableness.'" Brigham City v. Stuart, 547 U. S. 398, 403 (2006). Our cases have determined that "[w]here a search is undertaken by law enforcement officials to discover evidence of criminal wrongdoing, . . . reasonableness generally requires the obtaining of a judicial warrant." Vernonia School Dist. 47 J v. Acton, 515 U. S. 646, 653 (1995). Such a warrant ensures that the inferences to support a search are "drawn by a neutral and detached magistrate instead of being judged by the officer engaged in the often competitive enterprise of ferreting out crime." Johnson v. United States, 333 U. S. 10, 14 (1948). In the absence of a warrant, a search is reasonable only if it falls within a specific exception to the warrant requirement. See Kentucky v. King, 563 U. S. ____, ____ (2011)(slip op., at 5-6).

The two cases before us concern the reasonableness of a warrantless search incident to a lawful arrest. In 1914, this Court first acknowledged in dictum "the right on the part of the Government, always recognized under English and American law, to search the person of the accused when legally arrested to discover and seize the fruits or evidences of crime." Weeks v. United States, 232 U. S. 383, 392. Since that time, it has been well accepted that such a search constitutes an exception to the warrant requirement. Indeed, the label "exception" is something of a