Judicial harmonisation through autonomous concepts of European Union Law: The example of the European Arrest Warrant Framework decision

The Court of Justice of the European Union (CJEU) has been a key institutional actor to promoting legal integration within the EU. On many occasions, such a function has been performed to fill or supplement the harmonisation gap – intentionally or not – left by the Union legislature, especially in the context of secondary law. In this sense, an important tool resorted to by the CJEU to achieve closer integration, has been conferring the status of autonomous concept upon provisions of EU law, so reducing room for discretion of state authorities. Against this background, this article raises the following question: has the Court used the autonomous concept to pursue judicial harmonisation in areas where the main intention of the EU legislature was to preserve member states autonomy? The answer put forward in this research is in the affirmative. The hypothesis is tested by analysing the use of the autonomous concept in the context of the European Arrest Warrant Framework Decision (EAW FD), an instrument adopted in an area extremely sensitive to national sovereignty. By drawing on Tridimas’ distinction between outcome, guidance and deference cases, this article shows that the CJEU’s use of the autonomous concept in interpreting the EAW FD has had great potential in terms of harmonising effect.