The US missile defence shield in Europe has in just a few months become a subject of public debate, of contradictory statements, and has even gone as far as a geopolitical confrontation. Yet behind the media hype work has been under way on technical and operational issues that have raised the politico-military questions now in the public domain. It is worthwhile looking at some of this technical information in order to clarify the debate. For example, to understand the multinational dimension of a battle which could take place above European territory without any consultation between governments being possible in real time. Plans for this type of defence are under way now. It can be controlled as long as Europe has the will to expend a little effort to understand it, to be involved in it and to bring to it what will probably be a very timely contribution for the continent.