The role of the European Union (EU) in the international arena is not easy to understand. In the fields of trade and development cooperation the EU has been able to impose itself as an important actor, thanks to the effectiveness of its powers and the clarity of the existing procedures. But when it comes to diplomacy or security, things get more complicated. During the last years the European Institutions have certainly acquired important powers in the fields of foreign, security and defence policies (CFSP, ESDP), but the complexity of the institutional mechanisms ruling these competences and the unanimity system didn’t allow the EU to impose itself in a clearly defined role on the international arena. Thus, the result is a confusing framework, from which the EU appears and disappears according to the topic and the mood of the European Council members. Kosovo, Russia, Iraq, Iran, Middle East, Africa: when it doesn’t evaporate, the EU faces the great international security challenges each time in a different way and with a very variable influence capability ...