* The Smith Act of 1940 made it a criminal offense for anyone to knowingly or willfully advocate, abet, advise, or teach the duty, necessity, desirability, or propriety of overthrowing the government of the United States or of any state by force or violence; or for anyone to organize any association that teaches, advises, or encourages such an overthrow; or for anyone to become a member of or to affiliate with any such association.

Source: http://caselaw.lp.findlaw.com