The American Civil Liberties Union (ACLU) is a nonpartisan, non-profit, organization whose 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, lobbying, and community empowerment.[clarification needed] The ACLU has over 750,000 members and an annual budget of over $100 million. Local affiliates of the ACLU are active in all 50 states and Puerto Rico. The ACLU provides legal assistance in cases when it considers civil liberties to be at risk. Legal support from the ACLU can take the form of direct legal representation or preparation of amicus curiae briefs expressing legal arguments when another law firm is already providing representation.

In addition to representing persons and organizations in lawsuits, the ACLU lobbies for policies that have been established by its board of directors. Current positions of the ACLU include: opposing the death penalty; supporting same-sex marriage and the right of LGBT to adopt; supporting birth control and abortion rights; eliminating discrimination against women, minorities, and LGBT people; supporting the rights of prisoners and opposing torture; and opposing government preference for religion over non-religion, or for particular faiths over others.