((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;

((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.

((f)) Nothing in this section shall be construed as indicating an intent on the part of Congress to prevent any State, any possession or Commonwealth of the United States, or the District of Columbia, from exercising jurisdiction over any offense over which it would have jurisdiction in the absence of this section; nor shall anything in this section be construed as depriving State and local law enforcement authorities of responsibility for prosecuting acts that may be violations of this section and that are violations of State and local law.