Founded in 1920, the American Civil Liberties Union (ACLU) is a nonprofit, multi-issue, 500,000+ member public interest organization devoted to protecting the basic civil liberties of all people in the United States. Recognized as the nation’s premier public interest law firm, the ACLU works daily in courts, legislatures and communities to defend and preserve the freedoms guaranteed by the U.S. Constitution. The ACLU Foundation is the 501 (c)(3) arm of the organization.