The European Union (EU) was established on the basis of the Treaty of Rome signed in March 1957. At the Maastricht European Council in December 1991 the Heads of State and Government adopted a Treaty on Political Union a Treaty on Economic and Monetary Union which together form the Treaty on European Union.

The EU is composed of three "pillars": the European Community (EC), the Common Foreign and Security Policy (CFSC), and Justice and Home Affairs.

The Common Foreign and Security Policy (CFSP) is intended to be comprehensive and to cover all areas of foreign and security policy and to provide the framework for a European Security and Defence Policy (ESDP). In the Treaty of the European Union (1991), it was decided that the Western European Union (WEU) should be an integral part of the development of the Union. The operational role of the WEU has subsequently been assumed by the EU itself. In approving these measures, the EU leaders emphasised that NATO remained the foundation of the collective defence of its members and would continue to have an important role in crisis management. In addition, the EU decided to create permanent political and military structures, including a Political and Security Committee, a Military Committee and a Military Staff to ensure the necessary political guidance and strategic direction for such operations.

The EU-NATO Relationship

The EU and NATO decided to develop arrangements for full consultation, cooperation and transparency between both organisations. They agreed to create appropriate structures to ensure the necessary dialogue, consultation and cooperation with European NATO members which are not members of the EU, on issues related to European security and defence policy and crisis management. Ad hoc EU-NATO working groups were set up in mid-2000 to address these issues. Although agreement was soon reached in principle on most issues, real progress in putting in place practical arrangements for cooperation was more difficult to achieve. Discussions hinged on arrangements considered satisfactory by all Alliance member countries concerned for their participation in consultations and decision-making relating to the use of NATO assets by the EU.

A breakthrough was achieved in December 2002, enabling the EU and NATO to issue a joint Declaration on the European Security and Defence Policy, setting out agreed principles on which the future relationship between the two organisations would be founded.

Plans for establishing an EU military capability had been given expression at the EU summit in Helsinki in December 1999, with the announcement of a common European headline goal, to be achieved by 2003. The goal called for deployable military capabilities consisting of 60,000 troops, to be available within 60 days, sustainable for up to one year, to provide the means to enable the EU to carry out the full range of the so-called "Petersberg" tasks. These had been identified at a meeting of the WEU held in Germany in 1992 as the military tasks on which the European allies should concentrate their efforts. They consist of humanitarian and rescue tasks, peacekeeping tasks, and tasks of combat forces in crisis management including peacemaking.

The Alliance, for its part, has remained committed to reinforcing its European pillar through the development of separable but not separate capabilities which could respond to EU requirements and at the same time contribute to Alliance security.