http://en.wikipedia.org/wiki/Smith_Act...Prosecutions continued until a series of United States
Supreme Court decisions in 1957 threw out numerous
convictions under the Smith Act as unconstitutional. The
statute remains on the books, however.
http://www.english.uiuc.edu/maps/poets/g_l/jerome/smithact.htm...The Court had reaffirmed constitutional protections
regarding free speech and self-incrimination while raising
the requirement of "intent" to a level that made it
difficult for prosecutors to show a Communist Party member
had a criminal purpose. Nonetheless the Smith Act remained
and still remains on the books. Moreover, the prosecutions
had been very effective in destroying the momentum of the
Party and giving it a subversive image with the general
public which it has never totally shed.
http://www.infoplease.com/timelines/freespeech.html 1957 The Supreme Court modifies its 1951 holding
regarding the Smith Act. In Yates v. United States,
the Court overturned the conviction of several
Communist Party leaders under the Smith Act on the
grounds that merely urging a person to believe
something, as opposed to urging a person to do
something, can not be made illegal.