In the second session of the 110 th Congress, Members will likely exhibit an interest in NATO's effort to develop more mobile combat forces, enhance the alliance's role in Afghanistan, examine the appropriateness of a possible missile defense system for Europe, and enlargement of the alliance. Evolution of NATO and the EC/EU after the collapse of the Soviet Union in 1991 has brought with it some friction between the United States and several of its allies over the security responsibilities of the two organizations. These differences center around threat assessment, defense institutions, and military capabilities. However, there are disputes with the United States over how or whether to involve international institutions, such as the UN, in international crises. There are also disagreements over the weight given to political versus military instruments in resolving these crises. Congress is actively engaged in the evolving NATO-EU relationship. While Congress has supported the greater political integration that marked the European Community's evolution into the European Union, many Members have called for improved European military capabilities to share the security burden, and to ensure that NATO's post-Cold War mission embraces combating terrorism and WMD proliferation. The issues raised in the 1990s debate over European security remain the essence of the debate today. What are the missions in security affairs of NATO and the European Union? What is the proper weight to be given to political and military instruments in defending Europe and the United States from terrorism and proliferation? What types of military forces are necessary for NATO's role in collective defense, and for the EU's role in crisis management? Are NATO and EU decision-making structures and procedures appropriate and compatible to ensure that there is an adequate and timely response to emerging threats? U.S. At the same time, all allies underscore the importance of their strategic relationship with the United States. A New Security Actor: The European Union

For decades, there has been discussion within the EU about creating a common security and defense policy. They also hope that ESDP will give EU member states more options for dealing with future crises. Newer EU member states from central and eastern Europe, such as Poland and the three Baltic states, back ESDP but maintain that it must not weaken NATO or the transatlantic link. Administrations, backed by Congress, have supported the EU's ESDP project as a means to improve European defense capabilities, thereby enabling the allies to operate more effectively with U.S. forces and to shoulder a greater degree of the security burden. As noted previously, U.S. policymakers and Members of Congress insist that EU efforts to build a defense arm be tied to NATO. Some U.S. officials remain concerned, however, that France and a few other EU members may continue to press for a more autonomous EU defense identity that could rival NATO structures and ultimately destroy the indivisibility of the transatlantic security guarantee.
Since the end of the Cold War, both NATO and the European Union (EU) have evolved along with Europe's changed strategic landscape. While NATO's collective defense guarantee remains at the core of the alliance, members have also sought to redefine its mission as new security challenges have emerged on Europe's periphery and beyond. At the same time, EU members have taken steps toward political integration with decisions to develop a common foreign policy and a defense arm to improve EU member states' abilities to manage security crises, such as those that engulfed the Balkans in the 1990s.
The evolution of NATO and the EU, however, has generated some friction between the United States and several of its allies over the security responsibilities of the two organizations. U.S.-European differences center around threat assessment, defense institutions, and military capabilities. Successive U.S. administrations and the U.S. Congress have called for enhanced European defense capabilities to enable the allies to better share the security burden, and to ensure that NATO's post-Cold War mission embraces combating terrorism and countering the proliferation of weapons of mass destruction. U.S. policymakers, backed by Congress, support EU efforts to develop a European Security and Defense Policy (ESDP) provided that it remains tied to NATO and does not threaten the transatlantic relationship.
Most EU member states support close NATO-EU links, but also view ESDP as a means to give themselves more options for dealing with future crises, especially in cases in which the United States may be reluctant to become involved. A minority of EU countries, spearheaded traditionally by France, continue to favor a more autonomous EU defense identity. This desire has been fueled further recently by disputes with the United States over how or whether to engage international institutions, such as the United Nations, on security matters and over the weight given to political versus military instruments in resolving international crises.
This report addresses several questions central to the debate over European security and the future of the broader transatlantic relationship that may be of interest in the second session of the 110th Congress. These include what are the specific security missions of NATO and the European Union, and what is the appropriate relationship between the two organizations? What types of military forces are necessary for NATO's role in collective defense, and for the EU's role in crisis management? Are NATO and EU decision-making structures and procedures appropriate and compatible to ensure that there is an adequate and timely response to emerging threats? What is the proper balance between political and military tools for defending Europe and the United States from terrorism and weapons proliferation? What is the effect of enlargement on security and stability?
This report will be updated as events warrant. For more information, see CRS Report RL33627, NATO in Afghanistan: A Test of the Transatlantic Alliance, by [author name scrubbed], and CRS Report RS21372, The European Union: Questions and Answers, by [author name scrubbed].