This circuit encompasses North Carolina, South Carolina, Virginia, West Virginia, and Maryland–so faculty at public universities in these states should take note.  F.I.R.E. has a useful account of what the court did; an excerpt:

The case involves Stephen Porter, a tenured professor of Higher Education in North Carolina State’s Department of Leadership, Policy and Adult & Higher Education, where he teaches graduate-level statistics and data analysis. He complained several times in recent years that NC State’s diversity initiatives resulted in “abandoning rigorous methodological analysis in favor of results-driven work aimed at furthering a highly dogmatic view of ‘diversity,’ ‘equity,’ and ‘inclusion.’” Over the course of two years, he criticized these initiatives’ impact on the department’s higher ed degree program, with which he was affiliated, during a 2016 department meeting, in a Spring 2018 email to colleagues, and in a personal blog post written that fall.

As a result, NC State removed Porter from the higher ed program on grounds that he was insufficiently collegial. He sued….

In the 2006 case Garcetti v. Ceballos, the Supreme Court held that when government employees speak “pursuant to their official duties, the employees are not speaking as citizens for First Amendment purposes, and the Constitution does not insulate their communications from employer discipline.” But, critically, Garcetti made an exception for faculty at public institutions engaged in “speech related to scholarship or teaching.” 

The Fourth Circuit’s decision considerably narrows this exception, effectively placing faculty speech about shared institutional governance and decision-making beyond the First Amendment. The court reasoned that Porter did not speak as an academic, but rather “in his capacity as an employee,” concluding Porter’s speech “was not a product of his teaching or scholarship” and is, therefore, “unprotected.”

Thus, the court held, even though his comments concerned scholarship within his department, they were not made in class, or in relation to his personal scholarship or teaching, and, as such, did not qualify for protection.

Garcetti was a dangerous case (it involved a state prosecutor speaking out about what he thought were mistakes in his office), and, contrary to FIRE, it is not clear that it "made an exception for faculty at public institutions."  As I wrote previously (about Florida's ongoing efforts to violate the free speech and academic freedom rights of faculty):

Lurking in the background is the 2006 Supreme Court case of Garcetti, which held that “when public employees make statements pursuant to their official duties, the employees are not speaking as citizens for First Amendment purposes, and the Constitution does not insulate their communications from employer discipline.” Speech by a public employee which can be grounds for discipline after the fact can also presumably be proscribed outright.  Now Garcetti involved a prosecutor who claimed constitutional protection for a memo to his superiors about a warrant whose factual basis he deemed wanting.  The Court rejected the attorney’s claim, noting that “his expressions were made pursuant to his duties” in the prosecutor’s office.   But are not the teaching and writing of a professor at a public university all “expressions…pursuant to his duties”?

One of the dissenters in Garcetti, Justice David Souter, raised the worrying implications for academic freedom of the majority's decision.  This elicited the following concession from Justice Anthony Kennedy in the majority opinion:

"Justice Souter suggests today’s decision may have important ramifications for academic freedom, at least as a constitutional value. There is some argument that expression related to academic scholarship or classroom instruction implicates additional constitutional interests that are not fully accounted for by this Court’s customary employee-speech jurisprudence.  We need not, and for that reason do not, decide whether the analysis we conduct today would apply in the same manner to a case involving speech related to scholarship and teaching."

In other words, the Supreme Court simply left it open whether the Garcetti rule applies wholesale to professors at public universities.

So one silver lining in the 4th Circuit decision is that they effectively recognize that what I usually call "core" academic freedom (freedom in research and teaching) is exempt from the Garcetti rule; unfortunately, faculty speech about institutional business is not protected at all, it seems.  This will have an immense chilling effect on faculty concerned about how their institutions are conducting themselves.  The question now is whether other circuits will follow this approach, and what the Supreme Court will do if it gets the issue.  (My guess is the Supreme Court will agree with the 4th Circuit.)  

ADDENDUM:  This decision directly affects public universities in the 4th Circuit; most private universities have made a contractual commitment to their faculty to protect academic freedom in line with the AAUP interpretation of its scope.  So, in principle, private universities may continue to treat faculty speech on institutional governance matters as within the scope of the contractual right.