Plaintive tales of rampant liberalism among college professors are as old as the hills—as old as the professors themselves, for that matter. And, although many attempts to establish exactly how liberal professors rely on flawed methodologies, no one disputes that liberal academics outnumber conservative academics. The recurring question is why this is the case, and whether anyone should care. Some hold that the lack of conservatives risks enfeebling the minds of the nation’s youth and oppresses beleaguered conservative PhDs who are denied jobs out of petty political bias. Neither view likely has much basis in reality.

A recent survey conducted by the American Council of Trustees and Alumni has reignited this debate. The survey results suggest that many students at top American universities and colleges feel partisan political pressure from professors, and that those pressures more frequently come in the form of liberal ideology.

That educated Americans have strong political views should be no surprise. Very few people ever obtain the saintly objectivity that would allow them to view the world with a lack of political bias bordering on indifference. Only slightly more are able to feign that attitude in the name of academic debate. The question, then, is not whether professors should have the political biases that are their birthright, but whether universities like Harvard should put restrictions on political speech in the classroom.

Such a question supposes that college students are dry leaves, blown every which way by the offhanded comments and parenthetical remarks of authority figures. Most college students are, in fact, mature and critical individuals who can easily distinguish between ill-conceived rants and nuggets of political wisdom. To be sure, professors should not attempt to deceive their students about the factual basis or validity of their opinions, but this is as far as their obligation to impartiality extends. College students are adults who are perfectly able to make up their own minds on a range of issues. Whether a student takes a class on economic incentives or systems of oppression, he can be relied upon not to mindlessly parrot every word the teacher spouts, like some sort of evil zombie. Some bias is actually salutary, insofar as it spurs students to articulate their own views.

Such benign bias has its limits, of course. Professors should always question their students, but never heckle them or mock them. Students should not feel, in general, that they cannot get good grades without abandoning their true political views. But the number of cases of biased grading practices on account of political leanings is surely less severe than the problem of teaching fellow ignorance or poorly worded exams. Until cases of the persecution of conservatives appear on its campus, a college should refrain from exerting undue influence on a professor’s right to free and open expression.

A line must inevitably be drawn to prevent improper intimidation in the classroom, but we think it best to err on the side of academic freedom rather than to overzealously stamp out bias wherever it appears. At Harvard, at least, we are confident that the quality of the curriculum is sufficiently strong and even-handed. Where there are exceptions—and there are—there are other avenues for exposure to alternate perspectives, and there are generally multiple outlets to air grievances. Professors rarely treat their students as pitchers to be filled up with the correct mix of red and blue ideas, but as human beings who deserve a clear explication of all relevant viewpoints. Universities should try to eliminate the problem of poor teaching and disengaged faculty—not this shallow question of whether professors are conservative or liberal.