The Strategic Concept reflects the broad approach to stability and security outlined above. It recognises that security is based on political, economic, social and environmental considerations as well as defence. It reflects the unprecedented opportunity which now exists to achieve the Alliance's long-standing objectives by political means, in keeping with the undertakings made in Articles 2 and 4 of the North Atlantic Treaty. Each of these elements is designed to ensure that crises affecting European security can be prevented or resolved peacefully. The military dimension of the Alliance remains an essential factor if these goals are to be achieved.
Security is indivisible.
An attack on one member of the Alliance is an attack upon all. The presence of North American forces in and committed to Europe remains vital to the security of Europe, which is inseparably linked to that of North America. NATO's security policy is based on collective defence, including an integrated military structure as well as relevant cooperation and coordination agreements. The maintenance of an appropriate mix of nuclear and conventional forces based in Europe will be required for the foreseeable future. In the changed circumstances affecting Europe's security, NATO forces are being adapted to the new strategic environment and are becoming smaller and more flexible.