Judicial backsliding: a guide to collapsing the separation of powers

We have a highly developed theoretical and empirical literature on judicial independence, but there is less research on judicial backsliding: the process through which duly elected executives reduce court independence and thus collapse the separation of powers. We conceptualize judicial backsliding and argue that legislatures as well as executives are likely to be implicated in it. First, we confirm that populist leaders are more likely to engage in backsliding. Our main focus, however, is testing two contending theories of how legislatures might affect judicial backsliding. The judicial independence literature emphasizes the executive's partisan support in the legislature. An alternative approach considers institutional constraints on the executive, including those emanating from legislative powers. Using a unique data set on judicial backsliding episodes from 1990 to 2021, we find that a decrease in horizontal constraints on the executive is highly related to onsets of judicial backsliding. The degree of partisan support in the legislature is generally not significant, although supplementary empirical analysis and a case study show how it may operate to prolong episodes of judicial backsliding. The argument has wider implications for the study of judicial independence and for the role that executives, legislatures, and courts play in the backsliding process.