From legislative micromanagement to litigation evergreens: The rise of privatized enforcement of European Union law

Why do some EU laws generate persistent litigation while others remain dormant? This paper examines whether variation in EU judicial activity reflects legislative intent to promote private enforcement. Even as centralized enforcement by the European Commission has become more selective, EU lawmakers have increasingly invited private actors—individuals and firms—to trigger compliance from below. The core claim is that enforcement-oriented design choices are systematically associated with higher levels of litigation through the preliminary reference procedure. To study this relationship, the paper focuses on explicit legal hooks—textual causes for action that grant private actors procedural rights to initiate enforcement, either vertically against public authorities or horizontally against other private actors. These provisions serve as observable indicators of legislative intent. I examine whether laws containing such features are more likely to generate preliminary references before the Court of Justice of the European Union (CJEU). Empirically, the paper provides the first large-N, cross-policy area test of this argument. It draws on a new article-level dataset covering all original EU directives and regulations adopted between 1990 and 2020. Enforcement hooks are identified using a human-in-the-loop text classification pipeline combining a fine-tuned legal-domain BERT model with systematic human validation. Legislative acts are then linked to the preliminary references they generate over time. The results show that only a minority of EU laws explicitly invite private enforcement, yet these acts account for a disproportionate and growing share of preliminary references. Overall, the findings demonstrate that persistent EU litigation is closely tied to how lawmakers structure enforcement within the law itself.