We are pleased to welcome Prof. Ryan C. Black and Prof. Ryan J. Owens for this guest post. Ryan C. Black is Professor of Political Science at Michigan State University.  Ryan J. Owens is the George C. and Carmella P. Edwards Professor of American Politics and the Director of the Tommy G. Thompson Center on Public Leadership, both at the University of Wisconsin-Madison

Recently, we published a study that examined the influence of former Supreme Court law clerks when they return to the High Court to argue cases. We sought to examine two questions: Do former clerks influence their justices? If so, why?

Like a vine that grows toward sunlight, these questions reach toward some of the most normatively important topics in a constitutional republic.  What does it mean for a judicial tribunal to decide cases neutrally? At what point do personal connections supersede legal arguments? How can a court most effectively mete out justice?

Our results show that former clerks exert a significant—though focused—influence over justices. Former clerks are more likely to obtain their own justices’ votes than otherwise identical Supreme Court advocates who never clerked. In numerical terms, an attorney who once clerked for a particular justice has a 73% chance of capturing that justice’s vote, while an otherwise identical attorney who never clerked has only a 57% chance of winning that justice’s vote. Stated otherwise, a former clerk enjoys a 16% greater probability of winning her former justice’s vote than all other attorneys.

This 16% greater probability is substantively meaningful. We suspect nearly anyone would jump at the chance to improve their odds of winning a justice’s vote at all, let alone from 57% to 73%. To place our findings in context, a previous study found that a quality argument by an attorney increased his or her chances of winning by 11%. Our results are even larger, highlighting the sizable influence of former clerks.

The importance of our finding is particularly telling if the case seems headed to a 5-4 outcome. Improving the chances of shifting a 5-4 loss to a 5-4 victory by strategically employing a former clerk seems worth the investment for firms and their clients.  The same could be said of cases where the Court median’s position is unclear. Not sure which way the swing justice will go? Call in that justice’s former clerk to argue the case. It may be the difference between victory and defeat.

Having established that clerks do in fact influence their former justices, we then examined why they enjoyed such success.

We tested a number of theories for that success. One theory argued that former clerks are simply better lawyers or have greater legal knowledge than non-clerks, and their inherent skills make them more successful. While it is true that Supreme Court clerks are indeed intelligent, it is not the case that they are inherently better lawyers than non-clerks. If that was so, all former clerks would have performed better than all non-clerks. Yet, the data did not reveal that outcome. In fact, some former clerks are just as likely to capture some justices’ votes as non-clerks. This finding also casts doubt on the theory that former clerks prevail because they enjoy process expertise. If knowing how the Court operates gives former clerks an edge, all former clerks would perform better than all non-clerks. Again, they do not. It is also possible that former clerks work at better law firms with greater resources, which helps them win. But we examined that dynamic and still found a former clerk influence that is independent of resources.

After a series of tests, we discovered that former clerk influence turns on their personalized knowledge of their justice. Clerks work closely with their justices for a full year, and during that intense time period, they learn much about their justices—how they think, what kinds of cases they like, what sorts of legal arguments work best, and similar bits of information. When they return to the Court to argue as lawyers, they can employ that personalized information to win their former justice’s vote.

Of course, it is obvious that justices have come to trust their former clerks. In other words, it could be possible that the “causal arrow” points from justice to former clerk rather than from former clerk to justice. We suspect there is something to the argument that justices trust their former clerks and thus vote for their position. Still, that alternative theory likely does not explain the 16% increase we discover. After all, justices can also come to trust the information other attorneys provide them. Clerking definitely provides someone the opportunity to gain a justice’s trust, but so too does a lifetime of litigating before that justice. In other words, if justices simply vote for those they have come to trust, one would expect them to be just as likely to vote for successful (i.e., trustworthy) repeat players who never clerked as they would their former clerks. The results, however, show that justices are still more likely to vote for their former clerks even when compared against successful repeat litigators who never clerked. Personalized information matters.

One alternative approach to examine the impact of personalized information would be to examine how justices treat lower court opinions written by their former clerks who have gone on to become judges. If the personalized information is the currency we believe it is, then we should expect that justices might be more likely to take cases decided by their former clerks, particularly when their former clerks write dissents. Those judges will know what it takes to capture their former boss’s attention. Future scholarship should investigate this dynamic.

Personal information is gold. And, if our study has anything to say about it, former clerks are swimming in it.