I started in earnest reading about academic freedom a couple months ago. I'm quite perplexed. Lemme try to sort out a couple perplexities.
Historically, in the US, academic freedom and tenure have been intricately linked. Tenure's key legitimating purpose, it is said, is to protect academic freedom: a tenured professor cannot be fired without due process, so that professor cannot be eliminated by a university administration merely for unpopular, controversial, or critical utterances. (If true, this would mean that non-tenured faculty and all contingent faculty have no de jure right to academic freedom.) An immediate question that arises is: what kinds of utterance? Critical of the university administration? Critical of colleagues? Unpopular in one's disciplinary field of research? Unpopular politically according to dominant ideologies in the US? Controversial regarding electoral politics or political issues? Or regarding sexual mores, or the high cost of gasoline?
In significant and well-known cases of tenured professors being fired, typically what has led to the firing are comments that are rather outrageous, from the standpoint of dominant political ideology in the US. For instance, Ward Churchill called the dead from the World Trade Center terrorist attack "little Eichmanns," which was nasty of him.
It is not clear that due process is routinely followed in these cases. Instead, an administration abruptly fires a professor, and legal and quasi-legal proceedings ensue. AAUP is called in to investigate, lawsuits are filed, all hell breaks loose. But it isn't tenure that protects this professor from being fired.
The cases in which tenure does protect a professor are probably not well-known, precisely because the effort to fire a professor that runs afoul of academic freedom fails because due process is followed and protects the professor. Because we don't hear about the case (no doubt the process would be confidential), such cases don't present evidence that tenure protects academic freedom.
My skeptical assessment of this situation is that one would take tenure to protect academic freedom basically on faith. One would also take on faith what kinds of utterance would be protected.
Thus my first perplexity: whether tenure, viewed as a process, is something that can protect academic freedom. Not if tenure works the way Marc Bousquet describes the process in How the University Works. My own take on it is maybe slightly less trenchant than the always delightfully trenchant (to me anyway; he rubs a whole lotta people the wrong way) Bousquet.
When I've heard or talked to tenure-track professors, candidates for tenure, about their work lives, academic freedom does not come up. Workload is about all they can talk about, and they barely have time to talk about that. They are desperate to publish as much as they can, to teach whatever they are told to teach, and to do whatever mundane committee work they are told they have to do, in order to satisfy and overwhelmingly exceed stated requirements for tenure. If academic freedom is supposed to cover unpopular, controversial, or critical utterances, tenure candidates do not have academic freedom, because they would never go anywhere near such utterances before reaching tenure. Plus, everyone they talk to tells them this.
So, once tenured, professors have academic freedom, and let that criticism flow forth, yes? No. Once tenured, professors seek promotion to full professor status, and they do so by continuing the work they did as tenure candidates. Although they may acknowledge that tenure protects them from dismissal, they know it doesn't protect them from not being promoted.
Besides their own pecuniary interests, tenured professors who are more obliging would be prudent to consider what consequences their critical comments might bring upon their academic departments, colleagues, research funding, and other benefits bestowed by administration. Very nice tenured, full professors are extremely cautious to avoid critical intramural utterance because they believe that administration will punish their criticism by denying tenure to their colleagues, or by denying their departments a much-needed tenure-track employment "line," or by cutting their budgets outright.
This leads me to a second perplexity, for another day: Perhaps academic freedom is not supposed to protect intramural utterance? Or is only meant to protect utterance within an academic discipline?