18 U.S.C. § 1951 : US Code - Section 1951: Interference with commerce by threats or violence

      (a) Whoever in any way or degree obstructs, delays, or affects
    commerce or the movement of any article or commodity in commerce,
    by robbery or extortion or attempts or conspires so to do, or
    commits or threatens physical violence to any person or property in
    furtherance of a plan or purpose to do anything in violation of
    this section shall be fined under this title or imprisoned not more
    than twenty years, or both.
      (b) As used in this section - 
        (1) The term "robbery" means the unlawful taking or obtaining
      of personal property from the person or in the presence of
      another, against his will, by means of actual or threatened
      force, or violence, or fear of injury, immediate or future, to
      his person or property, or property in his custody or possession,
      or the person or property of a relative or member of his family
      or of anyone in his company at the time of the taking or
        (2) The term "extortion" means the obtaining of property from
      another, with his consent, induced by wrongful use of actual or
      threatened force, violence, or fear, or under color of official
        (3) The term "commerce" means commerce within the District of
      Columbia, or any Territory or Possession of the United States;
      all commerce between any point in a State, Territory, Possession,
      or the District of Columbia and any point outside thereof; all
      commerce between points within the same State through any place
      outside such State; and all other commerce over which the United
      States has jurisdiction.

      (c) This section shall not be construed to repeal, modify or
    affect section 17 of Title 15, sections 52, 101-115, 151-166 of
    Title 29 or sections 151-188 of Title 45.