The 14 petitioners, leaders of the Communist Party in California, were indicated in 1951 in a Federal District Court under 3 of the Smith Act and 18 U.S.C. 371 for conspiring (1) to advocate and teach the duty and necessity of overthrowing the Government of the United States by force and violence, and (2) to organize, as the Communist Party of the United States, a society of persons who so advocate and teach, all with the intent of causing the overthrow of the Government by force and violence as speedily as circumstances would permit. The indictment charged that the conspiracy originated in 1940 and continued down to the date of the indictment and that, in carrying it out, petitioners and their co-conspirators would (a) become members and officers of the Communist Party, with knowledge of its unlawful purposes, and assume leadership in carrying out its policies and activities, (b) cause to be organized units of the Party in California and elsewhere, (c) write and publish articles on such advocacy and teaching, (d) conduct schools for the indoctrination of Party members in suc