The history of the socialist movement in the United States spans a variety of tendencies, including anarchists, communists, democratic socialists, Marxists, Marxist–Leninists, Trotskyists and utopian socialists. It began with utopian communities in the early 19th century such as the Shakers, the activist visionary Josiah Warren and intentional communities inspired by Charles Fourier. Labor activists, usually Jewish, German, or Finnish immigrants, founded the Socialist Labor Party of America in 1877. The Socialist Party of America was established in 1901. By that time, anarchism also rose to prominence around the country. Socialists of different tendencies were involved in early American labor organizations and struggles. These reached a high point in the Haymarket massacre in Chicago, which founded the International Workers' Day as the main labour holiday around the world, Labor Day and making the eight-hour day a worldwide objective by workers organizations and socialist parties worldwide.
Under Socialist Party of America presidential candidate Eugene V. Debs, socialist opposition to World War I was widespread, leading to the governmental repression collectively known as the First Red Scare. The Socialist Party declined in the 1920s, but the party nonetheless often ran Norman Thomas for president. In the 1930s, the Communist Party USA took importance in labor and racial struggles while it suffered a split which converged in the Trotskyist Socialist Workers Party. In the 1950s, socialism was affected by McCarthyism and in the 1960s it was revived by the general radicalization brought by the New Left and other social struggles and revolts. In the 1960s, Michael Harrington and other socialists were called to assist the Kennedy administration and then the Johnson administration's War on Poverty and Great Society while socialists also played important roles in the civil rights movement.
Unlike in Western Europe, Australia, and New Zealand, a major socialist party has never materialized in the United States and the socialist movement in the United States was relatively weak in comparison.