Modeling Supreme Court strategic decision making: The congressional constraint

This paper addresses the contradictory results obtained by Segal (1997) and Spiller and Gely (1992) concerning the impact of institutional constraints on the U.S. Supreme Court's decision making. By adapting the Spiller and Gely maximum likelihood model to the Segal dataset, we find support for the hypothesis that the Court adjusts its decisions to presidential and congressional preferences. Data from 1947 to 1992 indicate that the average probability of the Court being constrained has been approximately one-third. Further, we show that the results obtained by Segal are the product of biases introduced by a misspecified econometric model. We also discuss how our estimation highlights the usefulness of Krehbiel's model of legislative decision making.