Court restructuring has become a salient national political issue, with proposals to increase the number of justices on the US Supreme Court gaining traction in response to various Court controversies. However, relatively little attention has been paid to state-level efforts, some successful, to increase the number of justices on state supreme courts. Although the number of justices on the US Supreme Court has not been changed since 1869, the size of most state supreme courts has been less stable. To place recent state supreme court expansions into context, this article analyzes the historical dynamics of state supreme court expansion. Analyzing an original dataset that includes every change made to the size of a state supreme court since 1789, it finds that court expansion has been more likely when the political competitiveness of a state is low and when state judicial selection and retention systems provide for lower levels of judicial independence.
