Defending Europe seeks to clarify the competing ambitions, the contrasting visions and the trans-Atlantic tensions related to the recent quest by Europe for autonomy in the sphere of security and defense. Scholars from both sides of the Atlantic explore the development of ESDI within NATO, the revival of the WEU and the launch of the EU's Common European Security and Defense Policy. Among the issues discussed are the Euro-American capabilities gap, concerns regarding decoupling, discrimination, and duplication, and the complications posed by NATO/EU enlargement. Two contrary conclusions debate whether ESDP is more likely to strengthen or undermine the Atlantic Alliance. This informative foray into the trans-Atlantic security and defense issues is a crucial addition to the ongoing dialogue concerning this shifting and evolving relationship.