A number of people asked me this question in light of my paper, An Empirical Study of Political Bias in Legal Scholarship (with Adam Chilton), which I discuss here. To answer this question, we obtained citation data from Gregory Sisk (see this paper for his methodology). The results (the number of articles that cite a specific professor over the last five years, averaged over each group) are below:
So the answer is “yes” (at a statistically significant level). It is interesting, and possibly puzzling, that non-donors are cited less often than both Democrats and Republicans are. Maybe articles with a political bent attract a greater number of responses, and so professors who do not write them are less frequently cited.
That said, what is the explanation for the more frequent citation of Republican professors? I can think of the following possibilities:
1. Liberal law faculties discriminate against Republicans by implicitly imposing a higher standard for hiring them. Thus, Republicans who are hired are better scholars than Democrats, and hence are cited more often, even if the scholars in the larger pool of potential hires are equivalent in ability.
2. Liberal law professors, being more numerous, write more papers than Republicans do (in aggregate). Because they must find someone to criticize in their papers, they end up citing Republicans frequently. Citations by Republican law professors are divided among the larger pool of Democratic professors, so on a per capita bases the latter are less frequently cited than the former.
3. The most distinctive ideas (whether correct or not) are produced by Republicans because they are better able to resist pressures to conform and to repeat conventional wisdom. Distinctive papers are more likely to be cited than papers that repeat old ideas.
4. Republican scholars cite other Republican scholars more frequently than Democratic scholars cite other Democratic scholars because Republicans, feeling beleaguered in the liberal academy, have a greater sense of solidarity, and help each other out through excessive citation.
Better data would allow one to explore these alternative explanations. I should include the usual caveat that many people doubt the reliability of citations as a measure of scholarly quality or influence.