The Federal Wiretap Act, sometimes referred to as Title III, was adopted in 1968 and expanded in 1986. It sets procedures for court authorization of real-time surveillance of all kinds of electronic communications, including voice, email, fax, and internet, in criminal investigations. It normally requires, before a wiretap can commence, a court order issued by a judge who must conclude, based on an affidavit submitted by the government, that there is probable cause to believe that a crime has been, is being, or is about to be committed. Terrorist bombings, hijackings and other violent activities are crimes for which wiretaps can be ordered. (The PATRIOT Act expanded the list of criminal statutes for which wiretaps can be ordered.) This authority is used to prevent as well as punish crimes: government can wiretap in advance of a crime being carried out, where the wiretap is used to identify planning and conspiratorial activities.
