Modeling Collegial Courts (3) : Adjudication Equilibria

We present a formal game theoretic model of adjudication by a collegial court. The model incorporates dispute resolution as well as judicial policy making and indicates the relationship between the two. It explicitly addresses joins, concurrences and dissents, and assumes 'judicial' rather than legislative or electoral objectives by the actors. The model makes clear predictions about the plurality opinion’s location in 'policy' space; the case’s disposition; and the size and composition of the disposition, join, and concurrence - coalitions. These elements of adjudication equilibrium vary with the identity of the opinion writer and with the location of the case. In general, the opinion is not located at the ideal policy of the median judge. The model suggests new directions for empirical work on judicial politics. This paper substantially revises a prior post 'Modeling Collegial Courts (3): Judicial Objectives, Opinion Content, Voting and Adjudication Equilibria.' The current version presents the model more clearly but it lacks a number of illustrative examples and figures that appear in the prior version