( abbr the ACLU )
a US organization that defends the rights of people under the US Constitution. It was involved in the legal case in 1954 that ended the system of separate schools for African Americans. The ACLU has sometimes been criticized for defending freedoms for everyone, as in 1978 when it supported the right of the Nazi Party in America to march. More recently it has opposed the introduction of prayers in public schools and, since September 11 , has fought against a reduction of civil rights in times of national emergency.