While domestic judges ultimately decide whether to refer questions to the Court of Justice of the European Union (CJEU), little is known about how the idea to refer is introduced in national litigation or about the decision (not) to refer. The preliminary ruling procedure (PRP) allows the CJEU to safeguard the uniformity of EU law, but that task can be hindered when national courts withhold questions. This article explores how often questions are sent to the CJEU, compared to the decisions not to refer, and to what extent referrals are driven by national judges acting on their own motion, compared to the parties. Despite challenges in accessing such data, an analysis of 728 referred and non-referred cases from all Swedish courts reveals that, although the PRP formally excludes party involvement, it is mostly the parties who raise the issue. However, they often struggle to have their questions referred. Importantly, 42 per cent of the questions sent came from the judges acting on their own initiative, sometimes against the parties’ wishes. Courts with a duty to refer show the highest tendency to request preliminary rulings, likely in part due to their legal obligation. These findings suggest that both judges and parties should be viewed as co-drivers of the PRP, nuancing narratives that emphasise one over the other. Nevertheless, most questions of EU law stay at the national level, adding to the large pool of questions that never reach the CJEU.
Isak Nilsson (2026) studied this question.