Disputes within the transatlantic alliance over the necessity and timing of the 2003 US-led war with Iraq and modalities of the reconstruction of that country have produced doubts about the future of transatlantic relations. This article will consider this future from a theoretical point of view: what does "realism," the oldest and (arguably) most reliable theory of international politics, suggest about the future of transatlantic relations? What are the larger forces that shape this issue? These questions will be examined in light of one of the most peculiar developments of the last decade: the European Security and Defence Policy (ESDP). Why does the EU, absent the Soviet Union, and largely sheltered under the umbrella of the mighty United States, choose to spent time and resources on such a project?