Abstract: While we have a highly-developed theoretical and empirical literature on judicial independence, there is less research on judicial backsliding: the process through which autocratic executives—often with legislative support—collapse the separation of powers. We seek to conceptualize judicial backsliding and theorize about how it occurs. We propose a general methodological approach to identifying episodes of backsliding that can be modified to suit the research interests of the community working on the judiciary in a comparative context. We find that constitutional review is a necessary condition of judicial backsliding and that it takes place not only as a result of executive actions but through collusion between executives and legislators.