ACLU
The ACLU is frequently asked to explain its defense of certain people or groups—particularly controversial and unpopular entities such as the American Nazis, the Ku Klux Klan, and the Nation of Islam. We do not defend them because we agree with them; rather, we defend their right to free expression and free assembly. Historically, the people whose opinions are the most controversial or extreme are the people whose rights are most often threatened. Once the government has the power to violate one person's rights, it can use that power against everyone. We work to stop the erosion of civil liberties before it's too late.
Since we can't take on every worthy case, we usually select lawsuits that will have the greatest impact, cases that have the potential for breaking new ground and establishing new precedents that will strengthen American freedoms.