Judicial Independence in U.S. States: The Influence of Political Competition on Legislative Threats to State Supreme Courts

The purpose of this study is to examine how political competition in state governments influences the independence of state supreme courts. This study adapts existing theories from comparative judicial research of democratic countries to the U.S. subnational context. Through a comparative study of 50 U.S. states, I test whether political dynamics in subnational entities align with existing transnational theories of political competition and judicial independence. Political competition in states is measured by the partisan composition of state legislatures, competitiveness of state elections, and partisan control of state branches of government. Judicial independence is measured using court-curbing legislation as a proxy, examining the number of bills proposed by the legislature which would limit the power and autonomy of state supreme courts. I hypothesize that increasing political competition and partisan division reduces the legislative bodies ability to act cohesively, decreasing the likelihood of unified legislative threats against the judiciary when the court's rulings are viewed as reducing the power of the legislature. As a result, state supreme courts would experience fewer threats of legislative restrictions and greater judicial independence in states with higher levels of political competition. My findings will contribute further to understanding the complex interplay between legislative authority and judicial independence, specifically adding to the understanding of how political competition influences legislative efforts to assert itself over the judicial branch. This has broader implications for understanding the nature of political competition, separation of powers, and the rule of law in the United States.