Last fall, I highlighted law professor Todd Pettys’s critique of a much-ballyhooed study by political scientists Lee Epstein, Christopher M. Parker, and Jeffrey A. Segal that purports to show that in First Amendment speech cases “the votes of both liberal and conservative justices tend to reflect their preferences toward the ideological groupings of the speaker.” I then called attention to the response from Epstein, Parker, and Segal and explained why I found it unpersuasive.

The Buffalo Law Review published a revised version of Pettys’s critique (one that includes his replies to Epstein, Parker, and Segal), and I was among those it invited to respond to Pettys’s article. In my brief response, I argue that “There is no reason to think that the tools of modern political science are capable of generating meaningful insights into whether in-group bias affects judicial decision-making.” From my closing paragraph:

I do not dispute the possibility that in-group bias might influence judicial decision-making. I simply do not see how studies like the one by Epstein, Parker, and Segal have any hope of meaningfully showing such influence. I am open to the possibility that statistical analysis of voting patterns might discover apparent anomalies that suggest avenues for further exploration. But that further exploration, if it is going to be fruitful, will have to involve the sometimes difficult and often contestable work of legal reasoning—work that is beyond the bounds that modern political scientists have imposed on themselves.