The Impact of Presidential Appointments to the U.S. Supreme Court: Cohesive and Divisive Voting within Presidential Blocs

Abstract

Previous research by Robert Dahl and others has argued that the predominant pattern of Supreme Court decisionmaking reflects the appointments Presidents make to the Court. But each President's impact on the Court's decisions may be limited if that President appoints multiple justices who fail to vote cohesively. In this article we evaluate the relative impact of five Presidents' appointments by focusing on the group behavior of blocs of presidential appointees, emphasizing the extent to which such blocs vote cohesively or fragment in determining actual case outcomes. After first constructing “cohesion scores” for these “presidential blocs” to test the level of cohesive voting within each bloc, we examine particular configurations of votes in order to evaluate each bloc's adherence to its appointing President's ideological expectations on various issues. We find that in order for the chief executive to wield the strong influence hypothesized by Dahl and others, three conditions must be met: (1) the President must have the opportunity to appoint one or more justices; (2) when multiple justices are appointed, they must vote cohesively relative to the Court as a whole; and (3) voting cohesion among multiple appointments must further the President's (and the political majority's) policy preferences. Among modern Presidents, these conditions were fulfilled only by the Nixon and Reagan appointments.