Judicialized Law‐Making and Opportunistic Enforcement: Explaining the EU's Challenge of National Defence Offsets

This article seeks to explain how the European Union (EU) – by challenging national defence offsets – managed to move into a highly sensitive policy area under formerly exclusive Member State competence. Whereas major accounts of integration depict defence policy as a least likely case, our process‐tracing analysis shows that the EU's recent challenge of defence offsets was a case of supranational self‐empowerment. We theorize two consecutive strategies of judicial politics, which the Commission employed at different policy stages to overcome opposition from Member States and defence firms against domestic policy change: judicialized law‐making and opportunistic enforcement. Both strategies depend on three scope conditions: expansive case law of the European Court of Justice (ECJ), its fit with policy priorities of the Commission and a credible threat of follow‐up litigation.