Measuring Legal Rules in the European Union

Is the Court of Justice of the European Union (CJEU) more responsive to legal arguments from EU institutions or from Member States? To answer this question, a core methodological challenge is to translate general LLMs embeddings into a specialized representation of legal rules. To address this, I develop a contrastive learning approach that projects general text embeddings into a refined semantic space capturing legal meaning. Using these distilled embeddings, I compare the semantic alignment between the Court’s rulings and the written positions of the European Commission and Member States. The findings will reveal which institutional actors the Court aligns with most closely and whether certain Member States exert disproportionate influence. This approach offers a promising new tool for systematically assessing the interplay of law and politics in EU judicial decision-making.