Amici Curiae and Dissensus on the U.S. Supreme Court


  • The author thanks Joseph Kearney and Thomas Merrill for generously sharing their data; Chris Nicholson for his exemplary research assistance; and Ernesto Calvo, Bob Carp, Tim Hellwig, Wendy Martinek, and Lisa Solowiej for their insightful comments on previous versions of this article. This research was supported in part by National Science Foundation Research Grant SES-0350416. The author is solely responsible for any errors in fact and/or judgment. A previous version of this article was presented at the 2005 Annual Meeting of the New York State Political Science Association.

*Department of Political Science, University of North Texas, 125 Wooten Hall, PO Box 305340, Denton, TX 76203-5340; email:


A great deal of empirical research has focused on explaining why U.S. Supreme Court Justices partake in nonconsensual opinion writing. However, little attention has been paid to the role of organized interests in contributing to a Justice's decision to write or join a separate opinion. I argue that a Justice's decision to engage in this behavior is a partial function of interest group amicus curiae participation in the Court. By providing the Justices with a myriad of information regarding how cases should be resolved, organized interests create ambiguity in the Justices' already uncertain decision making, at the same time providing them with a substantial foundation for concurring or dissenting opinions. I subject this argument to empirical validation by examining the Justices' decisions to author or join regular concurring, special concurring, and dissenting opinions during the 1946–1995 terms. The results indicate that organized interests play a considerable role in increasing dissensus on the Supreme Court.