(a) Whoever travels in interstate or foreign commerce or uses any facility of interstate or foreign commerce, including, but not limited to, the mail, telegraph, telephone, radio, or television, with intent— (1) to incite a riot ; or (2) to organize, promote, encourage, participate in, or carry on a riot ; or (3) to commit any act of violence in furtherance of a riot ; or (4) to aid or abet any person in inciting or participating in or carrying on a riot or committing any act of violence in furtherance of a riot and who either during the course of any such travel or use or thereafter performs or attempts to perform any other overt act for any purpose specified in subparagraph (A), (B), (C), or (D) of this paragraph— Shall be fined under this title, or imprisoned not more than five years, or both.

(b) In any prosecution under this section, proof that a defendant engaged or attempted to engage in one or more of the overt acts described in subparagraph (A), (B), (C), or (D) of paragraph (1) of subsection (a) and (1) has traveled in interstate or foreign commerce, or (2) has use of or used any facility of interstate or foreign commerce, including but not limited to, mail, telegraph, telephone, radio, or television, to communicate with or broadcast to any person or group of persons prior to such overt acts, such travel or use shall be admissible proof to establish that such defendant traveled in or used such facility of interstate or foreign commerce.

(c) A judgment of conviction or acquittal on the merits under the laws of any State shall be a bar to any prosecution hereunder for the same act or acts.

(d) Whenever, in the opinion of the Attorney General or of the appropriate officer of the Department of Justice charged by law or under the instructions of the Attorney General with authority to act, any person shall have violated this chapter, the Department shall proceed as speedily as possible with a prosecution of such person hereunder and with any appeal which may lie from any decision adverse to the Government resulting from such prosecution.

(e) Nothing contained in this section shall be construed to make it unlawful for any person to travel in, or use any facility of, interstate or foreign commerce for the purpose of pursuing the legitimate objectives of organized labor, through orderly and lawful means.