Since its inception, the European Security and Defense Policy (ESDP) has generated controversy and concern, especially in the United States. Although Washington has wanted a stronger European partner, it has also worried that a stronger ESDP could undermine NATO and weaken the transatlantic link. The debate over ESDP must be seen in the broader strategic context, which has been influenced by the war in Kosovo, the effort to strengthen European defense integration, the reorientation of U.S. strategic interests after the Cold War, and the Bush administration's penchant for unilateral action and its suspicion of multilateral organizations--as shown by its actions in Iraq. As ESDP proceeds, the United States and Europe need to ensure that it strengthens transatlantic relations: (1) The U.S. must accept that Europe needs some autonomous operational planning capability outside of NATO. (2) U.S. and European defense transformation must be closely harmonized. (3) How ESDP develops will depend in part on whether the U.S. maintains a unilateralist approach or returns to its former respect for multilateralism. (4) Europe should eschew efforts to develop the EU as a counterweight to the United States.