The second clause of the Fourth Amendment sets forth specific requirements for the issuance and use of a warrant:

Although the amendment does not specifically name the judicial officer before whom a warrant shall be sought, the courts have long held that the purpose of the amendment is to place the judgment of an independent magistrate between law enforcement officers and the privacy of citizens. The courts have also held that the Fourth Amendment authorizes invasion of that privacy only upon a showing that constitutes probable cause. It limits that invasion by specifying the person to be seized, the place to be searched, and the evidence to be sought.