Founded in 1920 as a response to the Palmer Raids, the American Civil Liberties Union (ACLU) is a nonpartisan, non-profit organization that seeks to defend the principles and freedoms embodied in the Bill of Rights. To accomplish this goal, the ACLU advocates for civil liberties in courts, legislatures, and communities all over the United States at both the federal and state level. As a result of its dedication, there is no non-governmental organization that has more frequently argued in front of the Supreme Court of the United States than the ACLU.

This high-profile exposure of the ACLU has given many people the impression that the ACLU is one large, national organization. In reality though, the ACLU is a network of state affiliates associated with a national office. There is an ACLU affiliate in every state and even one in Puerto Rico! This structure has allowed the ACLU to vigilantly and efficiently monitor civil liberty issues at all levels of government.