The Court of Justice and Treaty Revision: A Case of Strategic Leniency?

Abstract

Students of EU judicial politics have debated whether the threat of legislative override can influence the behaviour of the European Court of Justice. Yet because of the high political hurdles for the passage of Treaty amendments, Treaty revision has been dismissed as the "nuclear option", exceedingly effective but difficult to use and, therefore, unlikely to impact judicial decision making. However, in periods when Treaties are being renegotiated and until a formal agreement is reached on the details of the new provisions, the ability of member state governments to use Treaty revision to either punish or reward the Court should be greater. This, we argue, may induce the Court of Justice to display more leniency towards member states. We test this argument by comparing the outcome of infringement rulings coincident with revision to the outcome of infringement cases in normal periods. We find that the ECJ is significantly less likely to render an adverse ruling in years coinciding with a Treaty revision or, using an alternative unit of time, in the three months leading up to the formal signature of a Treaty revision. Because the Court tends, on balance, to have more to gain than to lose from a revision, we suggest that it has a strategic incentive to avoid antagonizing member states until the new institutional deal is finalized.

Keywords: Court of Justice; European Union; Multilevel Model; Bayesian Statistics

JEL Classification: N44; C11; C50; D74