Rachel Lu explores for National Review Online the dearth of conservatives among the ranks of college professors.

Give Nicholas Kristof credit. He really is trying to persuade liberal academics to be more welcoming toward conservatives. Twice within the last month Kristof has raised the issue in the pages of the New York Times, arguing that academic liberals have become “the illiberal ones” by marginalizing conservatives within the academy. In his latest, he even wrote that the disdainful attitude he has perceived toward Evangelical Christians “feels to me like bigotry.”

At moments like these, there is some temptation to sneer and shout, “Welcome to the world!” We shouldn’t. This was a significant gesture. A liberal New York Times columnist just used the b-word to refer to liberal academics. More amazing still, the purported targets of this bigotry are conservative Christians. That’s brave. If I had read such a piece in graduate school, I would have raced out to buy a copy of the paper so I could tape the column to my fridge.

Is it true? Clearly it is true that conservatives are dramatically underrepresented in the academy, particularly in the humanities. As Kristof notes, it is easier in many disciplines to find a self-described Marxist than to find a Republican. (And in fact, the numbers aren’t close. About 18 percent of social scientists self-identify as Marxists, whereas Republicans represent 7 to 9 percent.) That raises two further questions. Why has this happened? And is it a problem?

It is a problem, first and foremost because liberal intolerance adds to the insularity that is already undermining scholarship. When everyone in a scholarly community thinks in similar ways, echo chambers start to form, and sloppy studies or arguments are accepted with insufficient scrutiny.