Student activists across the nation are demanding the hiring of more minority faculty. At Claremont McKenna College, where I teach, students have pushed for faculty training to sensitize us to the ways implicit racial biases supposedly shape our hiring decisions. At neighboring Pomona College, activists insist that half of all new faculty positions must be offered to racial minorities by 2025. Whatever one makes of the merits of such demands for greater diversity, many of the arguments that inform them are far more powerful when extended to academia’s most underappreciated minority: conservative professors.

While campus activists say discrimination against professors of color is due to implicit biases, research shows that academics are often explicit about their bias against conservative job applicants. George Yancey’s study found that approximately 30 percent of sociologists confessed that if they knew a job seeker was a Republican, they would be less likely to support her candidacy. Job candidates who are members of the National Rifle Association and evangelicals fared even worse, perhaps because those affiliations are proxies for cultural conservatism. Yancey further found that many other disciplines in the social sciences were not any more tolerant than sociology. Yoel Inbar and Joris Lammers study of bias in the field of social psychology corroborated Yancey’s findings. What surprised the authors most, however, was just how frank so many psychology professors were about their biases. As Inbar told the Washington Times: “Usually you have to be pretty tricky to get people to say they’d discriminate against minorities.”

Conservatives are also far less well represented in academia than all current targets of affirmative action. Women, in fact, now receive some 60 percent of BA’s and a majority of all Ph.D.’s, prompting some feminists to declare the “end of men.” Of course, people of color are underrepresented in the professoriate, though not as much as campus activists sometimes suggest. While approximately 34 percent of all Americans self identify as black, Latino, or Asian, some 21 percent of all professors do likewise. Conservatives can only dream of being this well represented. While the 2012 National Election Survey found that 36 percent of all Americans self identify as conservative, a recent survey by Neil Gross and Solon Simmons place the percentage of conservative faculty at 4 percent in the humanities and 5 percent in the social sciences.

Of course, some particular racial groups are more poorly represented in the professoriate than others. But unlike conservatives, their representation is improving. For instance, while 7 percent of full professors identify as black or Latino, 12 percent of assistant professors do likewise.

Advocates for racial minorities further contend that hiring more professors of color will help minority students feel more at home in the university. That may well be true. But much evidence also suggests that conservative students feel uncomfortable in their universities. Education professors Stephen Porter and Paul Umbach report that conservative students often avoid majoring in the social sciences and humanities where knowledge has been politicized by the left. Amy Binder and Kate Wood’s ethnographic study also noted the same tendency among conservative student activists despite their strong interest in political and social issues.

Even though conservatives are arguably more marginal to academic life than racial minorities, some object that they should not be the targets of diversification efforts. Conservatives, after all, have not faced much discrimination outside academia’s walls. They are well represented in corporate America and in Congress,dddddddd to give just two examples.

Yet affirmative action was extended to white women in the 1970s even though they faced far less discrimination than racial minorities. White women were included not because they confronted serious discrimination in a large range of occupations, but largely because they increased diversity. As Richard Kahlenberg observed, the “compensatory argument did not work well for women” in particular. “[W]hite women are much less economically disadvantaged than blacks and can readily compete in a number of educational and employment arenas without preference.”

Today’s affirmative action’s defenders emphasize the idea of diversity. And since the primary purpose of diversifying faculties is to cultivate a “robust exchange of ideas,” as Justice Powell put it, there is no good reason to exclude conservatives. If we really want a robust exchange of ideas, shouldn’t our diversity policies focus on ideational diversity? And while there are many good reasons to oppose affirmative action in general, there is no coherent case for excluding conservatives in particular.

Jon A. Shields is associate professor of government at Claremont McKenna College and coauthor with Joshua Dunn of the forthcoming book, Passing on the Right: Conservative Professors in the Progressive University (Oxford, 2016).