Browder, according to his communist critics, also fell into a similar error. He overestimated the power of American capital and believed that, through planning, America could overcome for some time its economic problems. This theory of “organized capitalism,” these opponents said, was wrong. It revised Marxist principles, weakened the communist movement, and betrayed the “socialist future.” After 1945 the Communist Party, using Browderism as a weapon, entered into a new period of consolidation and loyalty to Soviet Russia. The Party apparatus was tightened and discipline strengthened. Security commissions, with almost unlimited powers, tested the “loyalty” of members and many were expelled. Increased restrictions on the admittance of new members were set up. The Party press, following the Moscow tack, inveighed against American “imperialism” and heaped abuse on the Marshall Plan, the Greece-Turkey Aid program, and the organization of a West European defense organization. The old-time Stalinist, William Z. Foster, was welding the Party into an anti-American weapon of the cold war. In 1948, for the first time since the 1920’s, the Party found itself on the defensive when the Department of Justice initiated prosecution against its leaders. The twelve members of the Party’s National Board were indicted under the Smith Act (enacted in 1940), which prohibits any conspiracy that advocates the overthrow of the United States government by force and violence. Previously, in 1941, the government had instituted prosecutions against members of the Socialist Workers Party (Trotskyites) under this statute. Other statutes since used by the government in the attack on the Party include the Internal Security Act of 1950 and the Communist Control Act of 1954. In a long trial, running through most of 1949, eleven members were convicted, the twelfth, William Z. Foster, having been severed from the trial because of illness. In June, 1951, the Supreme Court upheld these convictions, and the government subsequently took prosecutive action against additional Party leaders. This government prosecution was a strong disabling blow against the Party. Many of its top leaders were arrested and convicted. Others lived in fear of arrest. As a result the Party to a large extent went underground in the first large-scale underground operation since the early 1920’s. Party offices were closed, top Party leaders went into hiding, records were destroyed. Courier systems were instituted and clubs broken up into small units, if not completely disbanded. For about four years, from mid-1951 to mid-1955, the Party in protecting itself spent energy, time, and money that otherwise would have gone into agitation and propaganda.