Simultaneously, steps were taken to make provision for increased roles and responsibilities in the Alliance for the European Allies, in order to strengthen the European Security and Defence Identity. The 1991 Strategic Concept served its purpose well, guiding NATO from the Cold War towards a new and better European security environment. However, as the end of the decade approached, the need for further change became clear.

At the Washington Summit in April 1999, the NATO Allies approved a revised Strategic Concept to equip the Alliance for the security challenges and opportunities of the 21st century and to guide its future political and military development.

The 1999 Strategic Concept provides overall guidance for the development of detailed policies and military plans. It describes the Purpose and Tasks of the Alliance and examines its Strategic Perspectives in the light of the evolving strategic environment and of new security challenges and risks. Setting out the Alliance's Approach to Security in the 21st Century, the Concept reaffirms the importance of the transatlantic link and of maintaining the Alliance's military capabilities and examines the role of other key elements in the Alliance's broad approach to stability and security, including the European Security and Defence Identity; conflict prevention and crisis management mechanisms; partnership, cooperation and dialogue; NATO enlargement; and arms control, disarmament and non-proliferation.

Finally, the Concept gives Guidelines for the Alliance's Forces based on the principles of Alliance strategy and the characteristics of the military forces available to the Alliance. This includes sections addressing the missions of allied military forces and guidelines for their organisation, as well as the characteristics of conventional and nuclear forces.

The revised Strategic Concept, like its predecessor published in 1991, is the authoritative statement of the Alliance’s objectives. It provides the highest level political guidance on the means to be used in achieving them.

Historical Note

The initial formulation of NATO strategy was known as " The Strategic Concept for the Defence of the North Atlantic Area ". Developed between October 1949 and April 1950, it set out a strategy of large-scale operations for territorial defence. In the mid-1950s the strategy of "massive retaliation " was developed.