The debate over bias in the academy usually follows a predictable pattern. Conservatives tout a survey or study that says American college campuses are teeming with pinkos. Liberals assail the report as conservative propaganda. Conservatives mock liberals for denying the obvious.

The most recent skirmish in this cycle involves a report released in January, "The Faculty Bias Studies: Science or Propaganda?" Prepared by the education consultant John Lee and published by the American Federation of Teachers (AFT), the paper concludes that eight studies frequently cited by conservatives are rife with methodological flaws, errors, and biases of their own.

Some of the report's targets were quick to respond with countercharges. Anne Neal, president of the American Council of Trustees and Alumni (ACTA), told Inside Higher Ed that "AFT's report is not science-it's propaganda." Neal's group had produced two of the studies criticized by Lee.

The AFT report identifies some genuine problems with some widely publicized studies of campus bias. For instance, a major 2005 survey on faculty political leanings by Stanley Rothman, S. Robert Lichter, and Neil Nevitte cannot be properly peer-reviewed because the survey instrument has never been made public.

That said, some of Lee's nitpicks make little sense. Take ACTA's 2006 report "How Many Ward Churchills?," which focused on cultural and political radicalism in college curricula. The report can certainly be faulted for inflammatory rhetoric-the title refers to the University of Colorado professor who derided the victims of the 9/11 attack as "little Eichmanns"-but it doesn't make sense for Lee to attack it for a lack of scientific sampling, since it never claimed to be a scientific survey.

More broadly, Lee's attempt to challenge findings that most college professors are politically left of center seems pointless. The studies may be flawed, but their conclusion falls into the realm of the obvious. Even if you were to dismiss the Rothman-Lichter-Nevitte study, which found that 72 percent of full-time faculty identified as liberal while 15 percent considered themselves conservative and the rest middle of the road, there still remains the 2001 survey-never mentioned by Lee-by the Higher Education Research Institute (HERI) at UCLA. It found that about 5 percent of faculty members called themselves far left, 42 percent were liberal, 34 percent considered themselves middle of the road, less than 18 percent were conservative, and 0.3 percent placed themselves on the far right. (One likely reason for the difference between the two surveys is that the HERI study included two-year colleges in its sample.)

In 2005, when Penn State's Michael Bérubé wrote a long, snarky blog post assailing the Rothman-Lichter-Nevitte study and its right-wing sponsors, he went on to cite the HERI study and conceded, "Yes, we're a pretty liberal bunch."

The more interesting question, usually neglected in the wash-rinse-repeat cycle of the bias debate, is what danger, precisely, all this liberal dominance on campus poses to the nation. Are tenured radicals really brainwashing the young? For answers, you should look to the voting behavior and party identification of students and recent graduates, not their professors.

A recent poll by the Pew Research Center found that today's 18-to-25-year-olds are "the least Republican generation." In 2006, 48 percent of people in this age group identified themselves as Democrats or leaning Democratic; 35 percent were Republicans-the lowest result recorded since Pew started tracking the data in 1987. Meanwhile, Democrats carried the under-26 vote in the 2006 midterm elections by 58 percent to 37 percent.

So are the conservatives right? Is any of that attributable to the influence of college? Not necessarily: In the early 1990s, when college attendance was just as high and faculty ideologies skewed equally leftward, Republican identification in the same age group spiked to a record 55 percent.

While the HERI does an annual survey of incoming college freshmen that includes questions about political beliefs, no one has tried tracking changes in student political beliefs over the college years. One interesting glimpse is provided by HERI's 2004 report on political attitudes among freshmen and college graduates. In 1994, 82 percent of students in the class of 1998 agreed that "the federal government should do more to control the sale of handguns" and 61 percent agreed that abortion should be legal. In 1998, these opinions were held by, respectively, 83 percent and 65 percent of college graduates in that cohort.

Thus, while college-educated Americans appear to be much more liberal than the general population-at least on certain issues-they also seem to hold those views before they first enter a college classroom.

Other evidence that college students aren't necessarily dancing to the professors' political tune comes from post-9/11 data on opinions about U.S. military action. While opposition to U.S. strikes in Afghanistan was common among college faculty (as ACTA documented in its November 2001 report "Defending Western Civilization"), an overwhelming 79 percent of students supported the war in the fall of 2001. Granted, support in the general population was even higher: 92 percent.

The December 2005 ACTA study "Intellectual Diversity: Time for Action," another paper critiqued by Lee, attempted to measure political bias in the classroom with a survey of students at 50 top colleges and universities. Only 7 percent of the students strongly agreed with the statement, "On my campus, there are courses in which students feel they have to agree with the professor's political or social views in order to get a good grade." Then again, another 22 percent agreed "somewhat." Forty-six percent strongly disagreed. The results suggest that there is, at least, a perception of a problem.

Interestingly, only 21 percent of the students surveyed agreed either strongly or somewhat that some professors on their campus are "intolerant of certain political and social viewpoints." It should be noted that among the students who were surveyed, self-identified liberals outnumbered conservatives by 46 percent to 13 percent, and it is usually harder to notice bias against viewpoints to which you are unsympathetic.

What is difficult either to deny or to quantify is that, especially at the more prestigious colleges and universities, the social climate fosters a strong presumption of liberal like-mindedness and a marginalization of dissent. Being left of center is the norm, and it is freely assumed that other people around you, be they students or faculty members, will share in your joy at the Democratic victories in Congress or your dismay at the passage of a ballot initiative prohibiting racial preferences in college admissions. This can translate into not only a chilly climate for conservatives but in some cases outright hostility.

If a student doesn't subscribe to the campus orthodoxy, the likely effect is not to convert her but to alienate her from intellectual life. Others learn only about a narrow range of ideas. One woman, a Ph.D. student in the social sciences at a Midwestern university, told me recently that when she started reading conservative, libertarian, or otherwise heretical blogs, "it was a whole perspective I had never been exposed to before in anything other than caricature."

When that's the norm, the harm is less to dissenters than to the life of the mind. It's not good for any group of people to spend a lot of time listening only to like-minded others. It is especially bad for a profession whose lifeblood is the exchange of ideas.

Contributing Editor Cathy Young (cathy-young63@aol.com) is the author of Growing Up in Moscow (Ticknor & Fields) and Ceasefire! (Free Press). She blogs at cathyyoung.blogspot.com.