The Smith Act trials of Communist Party leaders in New York City from 1949 to 1958 were the result of US federal government prosecutions in the postwar period and during the Cold War between the Soviet Union and the United States. Leaders of the Communist Party of the United States (CPUSA) were accused of violating the Smith Act, a statute that prohibited advocating violent overthrow of the government. The defendants argued that they advocated a peaceful transition to socialism, and that the First Amendment's guarantee of freedom of speech and of association protected their membership in a political party. Appeals from these trials reached the US Supreme Court, which ruled on issues in Dennis v. United States (1951) and Yates v. United States (1957).