With the advent of empirical approaches to political science some 70 years ago, many of those who studied law and courts soon adopted similar approaches and began using data-intensive methods to help us understand judicial behavior and legal institutions. Most of the initial focus was on the U.S. Supreme Court and then, to a lesser extent, other federal courts, particularly the U.S. Courts of Appeals. State high courts received far less attention. This is despite the fact that no less a personage than the late William J. Brennan, who, while an associate justice on the U.S. Supreme Court and confronting minority status on a more conservative Supreme Court, wrote a seminal article for the Harvard Law Review in 1997 that called for new legal attention to State Supreme Courts for the protection of civil liberties (William J. Brennan, “State Constitutions and the Protection of Individual Rights,” Harvard Law Review 90, no. 3 (January 1977): 489–504, https://doi.org/10.2307/1340334).

Brennan was speaking of using these courts for normative goals; however, empirical scholarship also lagged in studying these courts. Although there were earlier important studies, it is in the past 25 years that political science scholarship has really heeded Brennan’s call and paid attention to these state courts. This work by Gibson and Nelson