Petitioner was convicted of violating the so-called membership clause of the Smith Act, which makes a felony the acquisition or holding of membership in any organization which advocates the overthrow of the Government of the United States by force or violence, knowing the purposes thereof. The indictment charged that from January 1946 to the date of its filing in 1954 the Communist Party of the United States was such an organization and that, throughout that period, petitioner was a member thereof with knowledge of the Partys illegal purpose and a specific intent to accomplish overthrow of the Government "as speedily as circumstances would permit." The jury was instructed that it could not convict unless it found that, within the 3-year limitation period, (1) the Party advocated the violent overthrow of the Government, in the sense of present "advocacy of action" to accomplish that end as soon as circumstances were propitious, and (2) petitioner was an "active" member of the Party, and not merely "a nominal, passive, inactive or purely technical" member,