Judicial Independence and Political Uncertainty: How the Risk of Override Affects the Court of Justice of the EU

There is broad agreement in the literature that international courts (ICs) make decisions with bounded discretion in relation to state governments. However, the scope of this discretion, and the determinants of its boundaries, are highly contested. In particular, the central mechanism in separation-of-powers models of judicial politics—the possibility of legislative override—has raised controversy. We argue that the uncertainty that judges face regarding the political reactions to their decisions has important and undertheorized implications for their behavior. On the one hand, cautious judges are likely to be attentive to signals that contain information about the probability of an unfavorable override. On the other hand, misjudgments of the political risks are likely to be made. Thus, the possibility of override is a significant factor affecting judicial behavior, but it is also a fairly blunt mechanism for balancing the independence and accountability of courts. The empirical study focuses on the Court of Justice of the European Union (CJEU), which has long been at the center of theory development regarding the legalization of world politics and the rise of international courts. The results demonstrate a strong correlation between the CJEU's rulings and the political signals it receives, in a pattern that goes beyond legal merit, and that fits with the override mechanism. State governments are crucial parts of the broader audience that defines the political boundaries of judicial discretion.