All or Nothing: Explaining the Size of Supreme Court Majorities

Abstract

In this Article, Professors Edelman and Sherry use a probabilistic model to explore the process of coalition formation on the United States Supreme Court. They identify coalition formation as a Markov process with absorbing states and examine voting patterns from twelve Court Terms. On the basis of their data, they conclude that Justices are reluctant to remain in small minorities. Surprisingly, however, they also find that a three-Justice minority coalition is less likely to suffer defections than a four-Justice minority coalition. This counterintuitive result suggests that while in general it is minority Justices rather than majority Justices who drive the process of coalition formation, five-Justice majorities may be particularly interested in attracting additional votes. The Article closes with suggestions for future research.