One study of 1,000 professors finds that Democrats outnumber Republicans at least seven to one in the humanities and social sciences. That imbalance, more than double what it was three decades ago, is intensifying because younger professors are more uniformly liberal than the older cohort that is retiring.

Another study, of voter registrations records, including those of professors in engineering and the hard sciences, found nine Democrats for every Republican at Berkeley and Stanford. Among younger professors, there were 183 Democrats, six Republicans.     

But we essentially knew this even before The American Enterprise magazine reported in 2002 of examinations of voting records in various college communities. Some findings about professors registered with the two major parties or with liberal or conservative minor parties:

     Cornell: 166 liberals, 6 conservatives.

     Stanford: 151 liberals, 17 conservatives.

     Colorado: 116 liberals, 5 conservatives.

     UCLA: 141 liberals, 9 conservatives.

The nonpartisan Center for Responsive Politics reports that in 2004, of the top five institutions in terms of employee per capita contributions to presidential candidates, the third, fourth and fifth were Time Warner, Goldman Sachs and Microsoft. The top two were the California university system and Harvard, both of which gave about 19 times more money to John Kerry than to George Bush.

But George Lakoff, a linguistics professor at Berkeley, denies that academic institutions are biased against conservatives. The disparity in hiring, he explains, occurs because conservatives are not as interested as liberals in academic careers. Why does he think liberals are like that? ``Unlike conservatives, they believe in working for the public good and social justice.'' That clears that up. 

A filtering process, from graduate school admissions through tenure decisions, tends to exclude conservatives from what Mark Bauerlein calls academia's ``sheltered habitat.'' In a dazzling essay in The Chronicle of Higher Education, Bauerlein, professor of English at Emory University and director of research at the National Endowment for the Arts, notes that the ``first protocol'' of academic society is the ``common assumption'' -- that, at professional gatherings, all the strangers in the room are liberals.

It is a reasonable assumption, given that in order to enter the profession, your work must be deemed, by the criteria of the prevailing culture, ``relevant.'' Bauerlein says various academic fields now have regnant premises that embed political orientations in their very definitions of scholarship:

Schools of education, for instance, take constructivist theories of learning as definitive, excluding realists (in matters of knowledge) on principle, while the quasi-Marxist outlook of cultural studies rules out those who espouse capitalism. If you disapprove of affirmative action, forget pursuing a degree in African-American studies. If you think that the nuclear family proves the best unit of social well-being, stay away from women's studies.

This gives rise to what Bauerlein calls the ``false consensus effect,'' which occurs when, due to institutional provincialism, ``people think that the collective opinion of their own group matches that of the larger population.'' There also is what Cass Sunstein, professor of political science and jurisprudence at the University of Chicago, calls ``the law of group polarization.'' Bauerlein explains: ``When like-minded people deliberate as an organized group, the general opinion shifts toward extreme versions of their common beliefs.'' They become tone-deaf to the way they sound to others outside their closed circle of belief.      

When John Kennedy brought to Washington such academics as Arthur Schlesinger Jr., John Kenneth Galbraith, McGeorge and William Bundy and Walt Rostow, it was said that the Charles River was flowing into the Potomac. Actually, Richard Nixon's administration had an even more distinguished academic cast -- Henry Kissinger, Pat Moynihan, Arthur Burns, James Schlesinger and others.

Academics, such as the next secretary of state, still decorate Washington, but academia is less listened to than it was. It has marginalized itself, partly by political shrillness and silliness that have something to do with the parochialism produced by what George Orwell called ``smelly little orthodoxies.''

Many campuses are intellectual versions of one-party nations -- except such nations usually have the merit, such as it is, of candor about their ideological monopolies. In contrast, American campuses have more insistently proclaimed their commitment to diversity as they have become more intellectually monochrome.

They do indeed cultivate diversity -- in race, skin color, ethnicity, sexual preference. In everything but thought.