The mission of the ACLU is to preserve all of these protections and guarantees:

Your First Amendment rights - freedom of speech, association and assembly; freedom of the press, and freedom of religion.
Your right to equal protection under the law - equal treatment regardless of race, sex, religion or national origin.
Your right to due process - fair treatment by the government whenever the loss of your liberty or property is at stake.
Your right to privacy - freedom from unwarranted government intrusion into your personal and private affairs.

http://www.aclu.org