The American Labor Party was formed in 1936 by socialist supporters of the New Deal and the re-election of President Franklin D. Roosevelt. Their leading politician was Vito Marcantonio, who was electedin 1938 to Congress as the representative of East Harlem's 20th District. In 1948 another Labor Party Congressman, Leo Isacson, was elected in a special election and served briefly.
Amid growing accusations that the American Labor Party was pro-communist, it began to lose its influence. Isacson lost his seat in the general election in 1948, and Marcantonio lost his in 1950. By 1956 the American Labor Party was effectively finished as a political force.