The aim of this article is twofold: first, to show, through a brief historical overview of the European Union (EU) and the European Atomic Energy Community (Euratom) in particular, why the latter has achieved a controversial status and is yet unlikely to be reformed by the Member States (MS). The second is to illustrate that, despite this deadlock, the Euratom Treaty has undergone a change in legal significance, driven in particular by the case law of the European Court of Justice (ECJ), with the result that conflicts between the two Treaty regimes are almost completely avoided.