Why do interest groups participate in state courts of last resort by filing amicus curiae briefs? Are they influential when they do? This dissertation examines these questions using an original survey of organized interests that routinely participate in state supreme courts, as well as data on all amicus curiae briefs and majority opinions in over 14,000 cases decided in all fifty-two state supreme courts for a four year period. I argue that interest groups turn to state judiciaries to achieve the dual goals of influencing policy and organizational maintenance, as amicus briefs can help organized interests achieve both outcomes. Furthermore, I contend that amicus briefs are influential in shaping judicial policy-making through the provision of legally persuasive arguments. The results suggest that interest groups do file amicus briefs to both lobby for their preferred policies and to support their organization's long-term viability. Additionally, the results indicate that organized interests also participate in counteractive lobbying in state courts of last resort by filing amicus briefs to ensure their side is represented and to dull the effect of oppositional amici. The findings also demonstrate support for the influence of amicus briefs on judicial policy-making on state high courts, as amicus briefs can influence the ideological direction of the court's majority opinions. Overall, this research extends our understanding of interest group lobbing in the judiciary and in state policy venues, and provides insight into judicial politics and policy-making on state courts of last resort.

While there has been a substantial body of research on interest group activity in U.S. federal courts, there has been comparatively little analysis of interest group engagement with state courts. Given that state courts adjudicate the vast majority of cases in the American legal system and very few cases are appealed to the Supreme Court, understanding why organized interests participate in these courts is of great importance. The present study analyzes interest group involvement as amicus curiae in all state courts of last resort from 1995-1999 to examine what factors motivate organized interests to turn to the courts. The results indicate that interest groups are primarily motivated by their policy goals in deciding which cases to file amicus briefs in, but that they are limited in their ability to file by institutional constraints unique to state courts of last resort. This research provides insight into interest group behavior, state courts and the role organized interests play in influencing legal outcomes in the American states.