Cases concerning the execution of the European Arrest Warrant (EAW) provide seemingly endless material for new questions of fundamental importance to the relationship of the multiple constitutional layers in Europe. In a barely noted judgment in the case of Romeo Castaño v. Belgium, the European Court of Human Rights has now added an important piece to this puzzle. The judgment indicates that, in the light of other recent jurisprudence of both the Court of Justice of the EU and the ECtHR, both Courts are on their way to find a workable framework to address some of the issues in this field.