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. It works through litigation, lobbying, and public education to address issues such as free speech, privacy, and discrimination. The ACLU engages in various legal battles to protect civil rights for all individuals, regardless of their background. It has played a significant role in landmark cases that have shaped American law, advocating for the rights of marginalized groups and ensuring that the principles of justice and equality are upheld.