It is not clear why the number of academic freedom cases seem to be increasing. Is it because the iron hand of ideological conformity is squeezing professors more tightly? Or is it because more subjects of attack are fighting back in court?
I tend to think it is for both those reasons. Socially acceptable views in academia tend to run from the left to the far left. More traditional, conservative viewpoints are regarded as simply wrong. It occurs in field after field. We see it on many aspects of the evolution debate and issues pertaining to bioethics. Academic freedom policies are adopted by universities, but then selectively applied. They probably were written to protect left wingers in dissent, so when a right winger tries to appeal to them, administrators regard the appeal as bizarre. Freedom of dissent is for liberals, not conservatives.
But groups like the Alliance Defense Fund (ADF) have been established in the past decade precisely to answer the cries of professors and students who are discriminated against on ideological grounds. As a consequence, some professors may be more willing now to sue.
In addition to evolution or bioethics, cases are coming to the fore on many fronts now. The ADF just won a settlement in California for a biology teacher who was assailed for providing an honest and scholarly answer to a question in class about the relative influence of nature versus environment in homosexuality. The Foundation for Individual Rights in Education (FIRE) and the ADF have entered another case by an Illinois professor who was denied promotion because someone was offended by his comparison of Catholic and utilitarian philosophies in evaluating sexuality.
Meanwhile, groups like the American Council of Alumni and Trustees is making some progress in forcing academia to live up to its own professed standards by adopting and enforcing serious codes of academic freedom. ACTA's own statement on the issue is preceded by a quote from former Yale president Benno Schmidt: "The most serious problems of freedom of expression in our society today exist on our campuses.... The assumption seems to be that the purpose of education is to induce correct opinion rather than to search for wisdom and to liberate the mind."