The American Association of University Professors (AAUP) serves as a
de facto authority on academic freedom, having published the guidelines by which most higher education institutions agree to abide, at least in principle if not legally.
AAUP, however, has no legal power to enforce its guidelines. The most it can do is put an institution on a "Censure List," which supposedly impacts the ability to recruit top faculty. I don't know whether it actually has that impact, but that's what's claimed.
The University of Illinois - Urbana Champaign (UIUC) was put on AAUP's Censure List after it refused to give a tenured position to controversial
hate-tweeting Prof. Seven Salaita. There was a lawsuit by Salaita that
was settled for less than the cost of defense without any job. AAUP now is considering whether to remove UIUC from its Censure List.
AAUP is jumping to the defense of Melissa Click, the world-famous "muscle prof" who
recently was terminated by the University of Missouri after she was caught on video bullying a student journalist and calling for some "muscle" from the crowd to deal with him.