Seizing opportunities: the determinants of the CJEU's deference to national courts

Recent studies of the preliminary reference procedure highlight that the Court of Justice of the European Union (CJEU) defers to national courts at higher rates than scholars initially expected. However, we know little about how the Court chooses which questions to leave for national courts to determine and which ones require its attention. I argue that the CJEU evaluates whether a referred question is representative of a broader set of cases nascent in European judiciaries. I expect that Member States expressing an interest in a reference signal that the Court's answer would have an impact on cases in European judiciaries beyond the dispute in the referring national court. Drawing on an original dataset covering more than 5,000 questions referred to the CJEU between 1995 and 2011, I show that the likelihood of the CJEU leaving legal questions unresolved decreases with the number of Member States submitting briefs to the Court.