Perspectives on Federalism is a free on-line peer-reviewed journal, promoted by the Centre for Studies on Federalism.

This paper analyses the case-law of the European Court of Justice on the substantive scope of ne bis in idem in transnational cases and evaluates the findings in light of the different concepts of legal interests inherent in the concept of crime as a material notion. I argue that the application of the interpretation of the ECJ to crimes against collective interests is insufficiently justified. As a result, the interpretation of ne bis in idem based on material facts appears only partially correct and a sense of distrust seems to be cemented between member states creating obstacles to a successful reform of the principle. Part one attempts to defend that the reasoning put forward by the court lacks validity and evaluates how this affects mutual trust. Part two analyses this interpretation in the light of different forms of legal interest. Part three examines how later case-law has tried to explain the problematic interpretation of early cases and its relationship with the Charter of Fundamental Rights of the European Union. The article will conclude by summarising the findings which may put into perspective the more general challenges of cooperation in criminal matters within the EU.