Another reason viewpoint diversity matters: Partisan bias can exceed racial bias
A few days before Fisher was argued but not in connection with the case, Ezra Klein of Vox amassed data suggesting that the greatest cleavages society were not between racial and ethnic groups, but between members of different political parties. A high percentage of members of both parties, for instance, expressed horror at thought of a daughter or son marrying outside the faith. Large majorities of both parties would be likely to hire a member of their party over that of another. As Ilya Somin has noted, such partisanship has troubling implications for democracy. Partisans will be more likely to dismiss opposing views reflexively, making beneficial decision making far less likely.
The Vox article McGinnis cites summarizes research testing partisan bias in the same way that racial bias has been tested in the past, using studies designed to uncover latent hostility or implicit favoritism. These studies show partisan bias affect the snap judgments individuals make about others and can even produce overt discrimination in contexts in which political ideology should be irrelevant. Here's Klein's summary of one such test:
Working with Dartmouth College political scientist Sean Westwood, [Stanford University's Shanto] Iyengar asked about 1,000 people to decide between the résumés of two high school seniors who were competing for a scholarship.
The resumes could differ in three ways: First, the senior could have either a 3.5 or 4.0 GPA; second, the senior could have been the president of the Young Democrats or Young Republicans club; third, the senior could have a stereotypically African-American name and have been president of the African-American Student Association or could have a stereotypically European-American name.
The point of the project was to see how political and cues affected a nonpolitical task - and to compare the effect with race. The results were startling.
When the résumé included a political identity cue, about 80 percent of Democrats and Republicans awarded the scholarship to their co-partisan. This held true whether or not the co-partisan had the highest GPA - when the Republican student was more qualified, Democrats only chose him 30 percent of the time, and when the Democrat was more qualified, Republicans only chose him 15 percent of the time.
Think about that for a moment: When awarding a college scholarship- a task that should be completely nonpolitical - Republicans and Democrats cared more about the political party of the student than the student's GPA. As Iyengar and Westwood wrote, "Partisanship simply trumped academic excellence."
It also trumped race. When the candidates were equally qualified, about 78 percent of African Americans chose the candidate of the same race, and 42 percent of European Americans did the same. When the candidate of the other race had a higher GPA, 45 percent of African Americans chose him, and 71 percent of European Americans chose him.
Implicit association tests produced similar results.
Why does this matter for universities? Back to McGinnis:
[A]ssuming we accept diversity as essential in higher education, it would seem that we need at least as much political diversity as diversity with respect to race and ethnicity. Students would learn about different political and ideological viewpoints if exposed to those espoused by Republican as well as Democrats, by conservatives as well as liberals. Indeed, political diversity provides a more direct way of gaining access to different viewpoints than relying on race and ethnicity, which are at best proxies for viewpoints. Society as whole would benefit because citizens would learn not to reflexively dismiss viewpoints. . . .
I am not arguing here that diversity should in fact be the reigning ideal of higher education. Other organizing principles, like a single focus on merit, have their own claims. But if indeed diversity is as important as all our university presidents, including my own, endlessly repeat, political and ideological diversity is at least as important as diversity measured by race and ethnicity.