Nicholas Georgakopoulos is the Harold R. Woodard Professor of Law, Indiana University Robert H. McKinney School of Law, Indianapolis. Frank Sullivan, Jr., is the Indiana University Bicentennial Professor at the same institution and was an Associate Justice of the Indiana Supreme Court from 1993 until 2012.

Could a graph display the ways that tight coalitions form on a supreme court? Wouldn’t it be interesting to juxtapose the corresponding arrangement of the justices in one subject matter, such as tort, to a different one, such as criminal procedure? We propose such a method of illustrating tight splits that also reveals all swing votes.

In this article, we develop a method for illustrating graphically (a) the majorities that issue tightly split opinions; (b) the swing votes between the different majorities; and (c) the opinions those majorities issue. We develop this method in the setting of the five-member Indiana Supreme Court as it was constituted between 1999 and 2010 using its composition as defined by its junior justice being Justice Robert D. Rucker. The other members of the court were Chief Justice Randall T. Shepard and Justices Brent E. Dickson, Frank Sullivan, Jr. (an author of this article), and Theodore R. Boehm. As the court’s membership did not change during that nearly eleven-year period, there were a substantial number–176–tightly split decisions. We examine them and observe many swing votes, varied coalitions, and differentiation by opinion subject matter. We develop graphical techniques to illustrate those different tendencies.

The principal contribution of this article is in laying the groundwork for visualizing and analyzing voluminous tightly split opinions, the majorities that produce them, and the corresponding swing votes. We posit that the placement of the majorities in a circle is more instructive than their placement in a parliament-like semicircle, which produces artificial extremes that are absent from the data. In the same context, we also develop tools to identify visually different alignments of a supreme court’s justices in different legal subject matters (i.e., topics or areas of law). We note that this resulting image of adjudication is markedly unlike what would appear if the median voter theorem applied.

We are not aware of any prior attempt to visualize voluminous supreme court data besides illustrations of the ideological position of justices. By contrast, many have identified swing votes with even scientific rigor and many have tried to identify differential attitudes of the United States Supreme Court by legal subject matter. Out of a vast expanse of literature, some milestones may be Andrew D. Martin, Kevin M. Quinn, and Lee Epstein, The Median Justice on the United States Supreme Court, 83 N.C.L. REV. 1275 (2005) (studying the voting of Justice O’Connor as the median justice) and Mark Klock, Cooperation and Division: An Empirical Analysis of Voting Similarities and Differences During the Stable Rehnquist Court Era–1994 to 2005, 22 CORNELL J.L. & PUB. POL’Y537 (2013) (studying details of what we term the Breyer composition). Others study the voting of justices on specific subject matters, for example, Lewis M. Wasserman and James C. Hardy, U.S. Supreme Court Justices’ Religious and Party Affiliation, Case-Level Factors, Decisional Era and Voting in Establishment Clause Disputes Involving Public Education: 1947-2012, 2 BRIT. J. AM. LEGAL STUD. 111 (2013) (studying the votes about the establishment clause in school finance cases). Others have studied the effect of unexpected features of the system, such as the bias of the Republican Party toward appointing younger justices, Jonathan N. Katz and Matthew L. Spitzer, What’s Age Got to Do with It? Supreme Court Appointees and the Long Run Location of the Supreme Court Median Justice, 46 ARIZ. ST. L.J. 41 (2014) (with a detailed discussion of the median justice theory and variations of it; supporting eighteen- year staggered terms for justices). One research method examines all coalitions to identify the median justice, Paul H. Edelman and Jim Chen, The Most Dangerous Justice: The Supreme Court at the Bar of Mathematics, 70 S. CAL. L. REV. 63 (1996). Our approach stands in contrast to attempts to identify a single justice as the swing vote because (a) we reveal all the swing votes; and (b) several swing votes are visibly material.  [Read entire Article here].