Are Even Unanimous Decisions in the United States Supreme Court Ideological?
Lee Epstein, William M. Landes, and Richard A. Posner

Northwestern University Law Review 106: 699-713 (2012)
Click here for the article
Click here for the data

Abstract

The fact that a substantial percentage of Supreme Court decisions are unanimous is often used to undermine the theory that the Court's decisions are ideologically driven. We argue that if the ideological stakes in a case are small, even slight dissent aversion is likely to produce a unanimous decision. The data support this interpretation but also establish the existence of an ideological effect in unanimous decisions. These findings are consistent with a realistic conception of the Court as a mixed ideological–legalistic judicial institution.

keywords: Supreme Court, unanimous decisions, judicial behavior, ideological influence, dissent aversion, legalistic decision-making, judicial voting patterns, court dynamics, case outcomes