Northwestern University Law Review
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.
Richard A. Posner, William M. Landes & Lee Epstein, "Are Even Unanimous Decisions in the United States Supreme Court Ideological?," 106 Northwestern University Law Review 699 (2012).