A Nebraska state trooper who was fired for joining a group linked to the Ku Klux Klan is getting legal support from a national group of state troopers.

The 40,000-member National Troopers Coalition, which has state trooper associations from 32 states as members, filed a legal brief with the Nebraska Supreme Court supporting Robert Henderson’s claim that he shouldn’t have been fired. Henderson was fired last year for joining the Knights Party, which describes itself as the most active Klan organization in the United States.