Existing above the accountability of elections, the Supreme Court?s legitimacy depends in part on the persuasiveness of its reasoning. In principle, the Court ought to justify its authority by providing logically coherent reasons for its decisions, that is the judgment in a case follows from premises supported by a majority of justices. If a decision of the Court is logically incoherent, then no rationale for its judgment carries a majority of justices. This study explores the occurrence, frequency, and impacts of logically incoherent decisions at the U.S. Supreme Court from 1946-2010. To address these puzzles, this project conducts three related analyses: first, identification of incoherent decisions in the aggregate over time and exploration of how institutional change affects coherence; second, investigation of the correlates of incoherent decisions in individual cases for evidence of legal or institutional factors at the case level which curb or encourage incoherence, while also identification of the areas of law are and least plagued by incoherence; and, third, determination of the extent to which incoherent decisions differ from others in their usage and treatment in the lower courts. This final analysis uses original data on lower circuit court citations in Supreme Court opinions.
This study provides the first systematic empirical evidence of the existence, correlates, and effects of logical incoherence. This evidence informs the lively debate among judicial reform advocates as some claim that the possibility of incoherence necessitates drastic reforms of courts, committees, boards, and other bodies while others argue against such dramatic action. Systematic evidence of the frequency and consequences of incoherence will move this debate forward. Further, a greater understanding of how the structure of judicial institutions affects the quality of their subsequent output and influence may provide guidance to actors creating new judiciaries, along with other collective decision making bodies. Additionally, one of the byproducts of the study will be a unique and rich dataset of lower court citations to Supreme Court opinions which should be of broad interest to scholars and practitioners.
