A FEW YEARS AGO, Brown University’s philosophy department interviewed a job applicant who was completing his graduate work at a university in a liberal town in an otherwise very red state. Since the state also has many scenic attractions, I asked him how he liked living there. He answered that he never ventured anywhere in the state outside the university town. Why not? “I’m afraid I might get kidnapped by Republicans,” he said.

I was tempted to reply, “I’m a Republican.” But my colleagues knew better and could blow my cover. So I settled for saying that it hardly reflected well on academia that someone could safely assume he knew the political views of professors who were strangers to him.

Liberalism among American professors raises much-discussed questions. Is there insufficient diversity of opinion on our campuses? If so, is there a cure that would not be worse than the disease? Another question gets far less discussion. How liberal are liberal professors when it comes to their own profession?

This last question is fun to ask but tricky to answer. Liberalism has many aspects. But surely a central aspect is that liberals claim to respect people’s rights, especially the rights of those low on the totem pole. Colleges and universities subvert students’ legal right to see their letters of recommendation. Colleges and universities “offer” students the “option” of waiving this right. Virtually all students “choose” this “option.” They realize that otherwise, their letters will probably not be taken seriously.

Virtually no other professors protest this subversion. Even my small step of showing all students my letters about them (despite the signed waivers) has found few followers.

Liberalism also involves concern with economic inequality and the plight of the have-nots. Academia offers ample scope for such concern. Salaries of faculty superstars can top $250,000, but part-time faculty often receive little, as do many non-professional employees. These disparities may be small in comparison with the business world, but they occur in an arena where, depending on the particular school, liberal professors might exert real influence. What if faculty superstars declined exorbitant salaries? What if other professors refused to let overpaid superstars join their departments? What if professors offered to forgo raises so the have-nots on their campus could get a better deal?

The standard defense of special salaries for special faculty is that this promotes excellence, which benefits both the school and the larger society. I have heard highly paid professors offer similar arguments for accepting grants from the National Endowment for the Humanities, National Science Foundation, or National Institutes of Health, grants funded by taxpayers, whose average income is far less than that of the grant recipients.

Do these arguments sound familiar? They should. They are what in other contexts liberals often reject as the trickle-down theory. Privileged professors may be liberals outside campus, but when it comes to their own careers, they turn into conservatives who believe that benefits directed at the privileged ultimately benefit society as a whole.

I wish I knew who was first to make that observation. Even more, I wish I had been first to make it, although it is oversimplified. Not all privileged professors are liberal. Not all liberal privileged professors claim that what is good for their careers is good for the country. For those who do, and who want to be consistent, four alternatives seem possible.

First, these professors can change their overall political orientation and endorse trickle-down economics in general as well as in academia.

Second, they can argue that their profession is a special case. This is not always ludicrous. National Institutes of Health grants may well lead to advances that benefit society. But in how many other cases will such a defense hold up?

Third, they can argue, as people sometimes argue in other contexts, that it is not always wrong to take advantage of an unjust system. Do you think this would let them off the hook here?

Fourth, they can start living their professional lives according to their own liberal principles.

Don’t hold your breath waiting.

Felicia Nimue Ackerman, a monthly contributor, is a professor of philosophy at Brown University.