The American Civil Liberties Union (ACLU) is a nonprofit organization founded in 1920 that focuses on defending and preserving individual rights and liberties guaranteed by the U.S. Constitution and laws. It works on a wide range of issues, including free speech, privacy rights, and equal protection under the law, often through litigation, advocacy, and public education. The ACLU operates through a network of affiliates across the United States, engaging in legal battles and policy advocacy to protect civil rights. It has played a significant role in landmark cases that have shaped American law and society, promoting justice and equality for all individuals.