Since Nicholas Kristof's "A Confession of Liberal Intolerance" will undoubtedly make the rounds, given its seemingly "countercultural" critique in favor of the GOP in academia, it is worth providing at least two specific responses to Kristof's argument. Kristof is merely sneaking power into the classroom, research, and publication through his argument, which is an unacceptable implication in any academic argument.
In the first place, it's ridiculous that any college professor would be represented by their political affiliation in the two-party system: no one is a good scholar or teacher or representing their scholarly viewpoint because they are GOP or Democrat. Even in "left-leaning" fields this would be absurd: it would matter less if two Sociologists or Anthropologists or Philosophers were Dem & GOP, rather than structuralist, feminist, Marxist, Foucauldian, Weberian, etc. [or not] (ironically, the same even goes for "right"-leaning fields, like Economics, where one can take a striking variety of ideological positions on institutionalism, corporate governance, Monetary policy, etc. It would obviously matter more, anyway, if one followed Keynes in economics, rather than political party).
Speaking especially as someone educated in fields that are publicly viewed as "left," there was not ever a time that I hoped my political theory prof would out themselves as Dem / GOP; it mattered much more what they had to say on Locke / Rousseau / Rawls / Arendt, etc. Philosophically, it would be absurd to suggest that political party affiliation matters in a debate about 20th century epistemology, or the Theory of Ideas from Plato to Aristotle, etc.; even fields colloquially aligned with what the USA calls "the left" have little-to-no-room for State parties in the classroom.
Suggesting that academia should correct for "political diversity" as "political party membership" in anyway is a great way to out oneself as an apologist for the State's political order itself, rather than a champion of academic freedom.
In this sense, given the GOP's extreme cultural victories from the ground-up, from roughly the 1970s-to-present, I find Kristof's argument about academic diversity disingenuous. Conservatives threw money at institutions to found right-leaning journals (stacking 2nd Amendment scholarship in their favor), to build law school curriculum and societies (creating The Federalist Society, an actual route to conservative judicial power), all the while even the most "groundbreaking" canonical political theorists of that time were "center" at best (Rawls, even as a welfare state theorist, was quite conservative). If anything, the GOP are a model for how a State-sponsored entity could maximize wings of academia for their agenda, instead of a model for "political academia outsider."
Anyway, the GOP has been an absolute force in local-state-Congressional election cycles, and they have effectively used academic infrastructures to create positions of strength in fields of cultural prestige or political monopoly (i.e., the judiciary). Acting as arms of the State, it's shortsighted (at best) to say that either Democratic or Republican views should be represented in the academy, and this point becomes even more dangerous when one considers the success that the GOP has had in the academy in terms of actually building ideology over the last 45-50 years.
This is simply shrouded power politics, and the implications for the right (that the GOP somehow is underrepresented in the academy) or the left (that representation as a Democrat in academic work) are both equally untenable.