50 U.S.C. § 1801 : US Code - Section 1801: Definitions

      As used in this subchapter:
        (a) "Foreign power" means - 
          (1) a foreign government or any component thereof, whether or
        not recognized by the United States;
          (2) a faction of a foreign nation or nations, not
        substantially composed of United States persons;
          (3) an entity that is openly acknowledged by a foreign
        government or governments to be directed and controlled by such
        foreign government or governments;
          (4) a group engaged in international terrorism or activities
        in preparation therefor;
          (5) a foreign-based political organization, not substantially
        composed of United States persons;
          (6) an entity that is directed and controlled by a foreign
        government or governments; or
          (7) an entity not substantially composed of United States
        persons that is engaged in the international proliferation of
        weapons of mass destruction.

        (b) "Agent of a foreign power" means - 
          (1) any person other than a United States person, who - 
            (A) acts in the United States as an officer or employee of
          a foreign power, or as a member of a foreign power as defined
          in subsection (a)(4) of this section;
            (B) acts for or on behalf of a foreign power which engages
          in clandestine intelligence activities in the United States
          contrary to the interests of the United States, when the
          circumstances of such person's presence in the United States
          indicate that such person may engage in such activities in
          the United States, or when such person knowingly aids or
          abets any person in the conduct of such activities or
          knowingly conspires with any person to engage in such
          activities;
            (C) engages in international terrorism or activities in
          preparation therefore;
            (D) engages in the international proliferation of weapons
          of mass destruction, or activities in preparation therefor;
          or
            (E) engages in the international proliferation of weapons
          of mass destruction, or activities in preparation therefor
          for or on behalf of a foreign power; or

          (2) any person who - 
            (A) knowingly engages in clandestine intelligence gathering
          activities for or on behalf of a foreign power, which
          activities involve or may involve a violation of the criminal
          statutes of the United States;
            (B) pursuant to the direction of an intelligence service or
          network of a foreign power, knowingly engages in any other
          clandestine intelligence activities for or on behalf of such
          foreign power, which activities involve or are about to
          involve a violation of the criminal statutes of the United
          States;
            (C) knowingly engages in sabotage or international
          terrorism, or activities that are in preparation therefor,
          for or on behalf of a foreign power;
            (D) knowingly enters the United States under a false or
          fraudulent identity for or on behalf of a foreign power or,
          while in the United States, knowingly assumes a false or
          fraudulent identity for or on behalf of a foreign power; or
            (E) knowingly aids or abets any person in the conduct of
          activities described in subparagraph (A), (B), or (C) or
          knowingly conspires with any person to engage in activities
          described in subparagraph (A), (B), or (C).

        (c) "International terrorism" means activities that - 
          (1) involve violent acts or acts dangerous to human life that
        are a violation of the criminal laws of the United States or of
        any State, or that would be a criminal violation if committed
        within the jurisdiction of the United States or any State;
          (2) appear to be intended - 
            (A) to intimidate or coerce a civilian population;
            (B) to influence the policy of a government by intimidation
          or coercion; or
            (C) to affect the conduct of a government by assassination
          or kidnapping; and

          (3) occur totally outside the United States, or transcend
        national boundaries in terms of the means by which they are
        accomplished, the persons they appear intended to coerce or
        intimidate, or the locale in which their perpetrators operate
        or seek asylum.

        (d) "Sabotage" means activities that involve a violation of
      chapter 105 of title 18, or that would involve such a violation
      if committed against the United States.
        (e) "Foreign intelligence information" means - 
          (1) information that relates to, and if concerning a United
        States person is necessary to, the ability of the United States
        to protect against - 
            (A) actual or potential attack or other grave hostile acts
          of a foreign power or an agent of a foreign power;
            (B) sabotage, international terrorism, or the international
          proliferation of weapons of mass destruction by a foreign
          power or an agent of a foreign power; or
            (C) clandestine intelligence activities by an intelligence
          service or network of a foreign power or by an agent of a
          foreign power; or

          (2) information with respect to a foreign power or foreign
        territory that relates to, and if concerning a United States
        person is necessary to - 
            (A) the national defense or the security of the United
          States; or
            (B) the conduct of the foreign affairs of the United
          States.

        (f) "Electronic surveillance" means - 
          (1) the acquisition by an electronic, mechanical, or other
        surveillance device of the contents of any wire or radio
        communication sent by or intended to be received by a
        particular, known United States person who is in the United
        States, if the contents are acquired by intentionally targeting
        that United States person, under circumstances in which a
        person has a reasonable expectation of privacy and a warrant
        would be required for law enforcement purposes;
          (2) the acquisition by an electronic, mechanical, or other
        surveillance device of the contents of any wire communication
        to or from a person in the United States, without the consent
        of any party thereto, if such acquisition occurs in the United
        States, but does not include the acquisition of those
        communications of computer trespassers that would be
        permissible under section 2511(2)(i) of title 18;
          (3) the intentional acquisition by an electronic, mechanical,
        or other surveillance device of the contents of any radio
        communication, under circumstances in which a person has a
        reasonable expectation of privacy and a warrant would be
        required for law enforcement purposes, and if both the sender
        and all intended recipients are located within the United
        States; or
          (4) the installation or use of an electronic, mechanical, or
        other surveillance device in the United States for monitoring
        to acquire information, other than from a wire or radio
        communication, under circumstances in which a person has a
        reasonable expectation of privacy and a warrant would be
        required for law enforcement purposes.

        (g) "Attorney General" means the Attorney General of the United
      States (or Acting Attorney General), the Deputy Attorney General,
      or, upon the designation of the Attorney General, the Assistant
      Attorney General designated as the Assistant Attorney General for
      National Security under section 507A of title 28.
        (h) "Minimization procedures", with respect to electronic
      surveillance, means - 
          (1) specific procedures, which shall be adopted by the
        Attorney General, that are reasonably designed in light of the
        purpose and technique of the particular surveillance, to
        minimize the acquisition and retention, and prohibit the
        dissemination, of nonpublicly available information concerning
        unconsenting United States persons consistent with the need of
        the United States to obtain, produce, and disseminate foreign
        intelligence information;
          (2) procedures that require that nonpublicly available
        information, which is not foreign intelligence information, as
        defined in subsection (e)(1) of this section, shall not be
        disseminated in a manner that identifies any United States
        person, without such person's consent, unless such person's
        identity is necessary to understand foreign intelligence
        information or assess its importance;
          (3) notwithstanding paragraphs (1) and (2), procedures that
        allow for the retention and dissemination of information that
        is evidence of a crime which has been, is being, or is about to
        be committed and that is to be retained or disseminated for law
        enforcement purposes; and
          (4) notwithstanding paragraphs (1), (2), and (3), with
        respect to any electronic surveillance approved pursuant to
        section 1802(a) of this title, procedures that require that no
        contents of any communication to which a United States person
        is a party shall be disclosed, disseminated, or used for any
        purpose or retained for longer than 72 hours unless a court
        order under section 1805 of this title is obtained or unless
        the Attorney General determines that the information indicates
        a threat of death or serious bodily harm to any person.

        (i) "United States person" means a citizen of the United
      States, an alien lawfully admitted for permanent residence (as
      defined in section 1101(a)(20) of title 8), an unincorporated
      association a substantial number of members of which are citizens
      of the United States or aliens lawfully admitted for permanent
      residence, or a corporation which is incorporated in the United
      States, but does not include a corporation or an association
      which is a foreign power, as defined in subsection (a)(1), (2),
      or (3) of this section.
        (j) "United States", when used in a geographic sense, means all
      areas under the territorial sovereignty of the United States and
      the Trust Territory of the Pacific Islands.
        (k) "Aggrieved person" means a person who is the target of an
      electronic surveillance or any other person whose communications
      or activities were subject to electronic surveillance.
        (l) "Wire communication" means any communication while it is
      being carried by a wire, cable, or other like connection
      furnished or operated by any person engaged as a common carrier
      in providing or operating such facilities for the transmission of
      interstate or foreign communications.
        (m) "Person" means any individual, including any officer or
      employee of the Federal Government, or any group, entity,
      association, corporation, or foreign power.
        (n) "Contents", when used with respect to a communication,
      includes any information concerning the identity of the parties
      to such communication or the existence, substance, purport, or
      meaning of that communication.
        (o) "State" means any State of the United States, the District
      of Columbia, the Commonwealth of Puerto Rico, the Trust Territory
      of the Pacific Islands, and any territory or possession of the
      United States.
        (p) "Weapon of mass destruction" means - 
          (1) any explosive, incendiary, or poison gas device that is
        designed, intended, or has the capability to cause a mass
        casualty incident;
          (2) any weapon that is designed, intended, or has the
        capability to cause death or serious bodily injury to a
        significant number of persons through the release,
        dissemination, or impact of toxic or poisonous chemicals or
        their precursors;
          (3) any weapon involving a biological agent, toxin, or vector
        (as such terms are defined in section 178 of title 18) that is
        designed, intended, or has the capability to cause death,
        illness, or serious bodily injury to a significant number of
        persons; or
          (4) any weapon that is designed, intended, or has the
        capability to release radiation or radioactivity causing death,
        illness, or serious bodily injury to a significant number of
        persons.