I was recently given a copy of Bernard Schwartz's entertaining book, A Book of Legal Lists, which includes lists of both the 10 greatest and 10 worst US supreme court justices. Those chapters reminded me of an article I wrote with my friend (and, regretably, former colleague) Mitu Gulati a few years ago, in which we had occasion to make an objective empirical evaluation of greatness on the part of modern supreme court justices.
As a proxy for the importance of cases decided by the Supreme Court, we looked at opinions that found their way into the casebooks. Specifically, we looked at thirty-eight currently used case books on Corporations, Business Associations, Securities Regulation, and Corporate Finance. For each casebook, we counted the number of securities and corporate opinions by the various Supreme Court justices. If the same case appeared in two casebooks, it was counted twice, and so on. We assumed more important cases would appear in more casebooks and that greatness would translate into a justice being assigned the most important (and most often reproduced) cases.
The table reveals a dramatic dominance effect for the late Justice Lewis Powell, both in terms of his overall number of securities and corporate cases in casebooks and his per year entry rate. In terms of total cases, Powell has sixty-one and only two other justices have more than 20 (White (22) and Blackmun (21); Marshall comes next closest with 19). A similar skew is present in the per year entry rates. Powell has an average of four securities or corporate cases entering the casebooks per year. The next closest number is 1.25. Finally, note that these are only comparisons for only those justices who have securities or corporate cases in the casebooks. Most have none. So, for our purposes, Lewis Powell ranks as the Greatest Supreme Court Justice. Your mileage, of course, may vary.
An alternate to the expertise/greatness hypothesis might be that Powell was simply a superior casebook opinion writer. While we did not test this alternate hypothesis, anecdotal evidence suggests that Powell did not having anything close to the same level of influence in other areas. He was an excellent opinion writer and among the more influential justices of his time. But his clear dominance was limited to the business areas. See Richard A. Posner, Cardozo: A Study in Reputation (1990) (commenting on Powell’s skill at opinion writing and comparing the influence levels of a set of different justices); Montgomery N. Koma, Measuring the Influence of Supreme Court Justices, 27 J. Legal Stud. 333 (1998) (ranking the justices according to influence levels as measured by citations).
