This chapter surveys four overlapping contexts in which scholars have examined institutional interactions between U.S. courts and legislatures. First, some have sought to explain when and why judges exercise the power of judicial review by invalidating democratically enacted statutes. Second, “regime politics” scholars have examined the political foundations of judicial power over time, emphasizing that courts have developed, retained, and expanded the authority to alter policy outcomes only because (and to the extent that) governing legislative coalitions have supported these developments. Third, some scholars have examined the range of legislative responses to assertions of judicial power, emphasizing that the judicial interpretation or even invalidation of a legislative policy is often far from the final word on the policy conflict in question. Fourth, some scholars have advocated an “interbranch perspective” on the policy process. This fourth approach has significant potential to advance existing understandings of the relationship between courts and legislatures.