He was the only one convicted after the Yates decision.[1][157] Prosecutors pursued Scales' case because he specifically advocated violent political action and gave demonstrations of martial arts skills.[3] Scales was accused of violating the membership clause of the Smith Act, not the clause prohibiting advocacy of violence against the government.[158] In his appeal to the Supreme Court, Scales contended that the 1950 McCarran Internal Security Act rendered the Smith Act's membership clause ineffective, because the McCarran Act explicitly stated that membership in a communist party does not constitute a per se violation of any criminal statute.[159][160] In 1961, the Supreme Court, in a 5–4 decision, upheld Scales' conviction, finding that the Smith Act membership clause was not obviated by the McCarran Act, because the Smith Act required prosecutors to prove first, that there was direct advocacy of violence; and second, that the defendant's membership was substantial and active, not merely passive or technical.[161][162] Two Justices of the Supreme Court who had supported the Yates decision in 1957, Harlan and Frankfurter, voted to uphold Scales' conviction.[8]