The American Civil Liberties Union (ACLU) consists of two separate non-profit organizations: the ACLU Foundation, a 501(c)(3) organization which focuses on litigation and communication efforts, and the American Civil Liberties Union, a 501(c)(4) organization which focuses on legislative lobbying. The ACLU's stated mission is "to defend and preserve the individual rights and liberties guaranteed to every person in this country by the Constitution and laws of the United States." It works through litigation, legislation, and community education. Founded in 1920 by Crystal Eastman, Roger Baldwin and Walter Nelles, the ACLU was the successor organization to the earlier National Civil Liberties Bureau founded during World War I. The ACLU reported over 500,000 members at the end of 2005.

Lawsuits brought by the ACLU have been influential in the evolution of Constitutional law. The ACLU provides legal assistance in cases in which it considers civil liberties to be at risk. Even when the ACLU does not provide direct legal representation, it often submits amicus curiae briefs.

Outside of its legal work, the organization has also engaged in lobbying of elected officials and political activism. The ACLU has been critical of elected officials and policies of both Democrats and Republicans.

History

Roger Nash Baldwin became head of the National Civil Liberties Bureau (NCLB) in 1917. An independent outgrowth of the American Union Against Militarism, the Bureau opposed American intervention in World War I. The NCLB provided legal advice and aid for conscientious objectors and those being prosecuted under the Espionage Act of 1917 or the Sedition Act of 1918. In 1920, the NCLB changed its name to the American Civil Liberties Union, with Baldwin continuing as its director and Walter Nelles as chief counsel. Jeannette Rankin, Jane Addams, Crystal Eastman, Albert DeSilver, Helen Keller, along with other former members of the NCLB, assisted Baldwin with the founding of the ACLU. Among the founding members was Felix Frankfurter, who later became an Associate Justice of the Supreme Court of the United States. DeSilver and Nelles were Baldwin's closest associates.

The ACLU was formed to protect aliens threatened with deportation, along with U.S. nationals threatened with criminal charges by U.S. Attorney General Alexander Mitchell Palmer for their communist or socialist activities and agendas"A Brief History of the American Civil Liberties Union", Champaign County ACLU. (see Palmer Raids). It also opposed attacks on the rights of the Industrial Workers of the World (IWW) and other labor unions to meet and organize.

In 1940, the ACLU formally barred communists from leadership or staff positions, and would take the position that it did not want communists as members either. The board declared that it was "inappropriate for any person to serve on the governing committees of the Union or its staff, who is a member of any political organization which supports totalitarianism in any country, or who by his public declarations indicates his support of such a principle." The purge, which was led by Baldwin, himself a former supporter of communism, began with the ouster of Elizabeth Gurley Flynn, a member of both the Communist Party USA and the Industrial Workers of the World.