The North Atlantic Treaty Organization is an intergovernmental military alliance based on the Washington Treaty, which was signed on 4 April 1949. The organization constitutes a system of collective defence whereby its member states agree to mutual defence in response to an attack by any external party. NATO’s Headquarters are located in Haren, Brussels, Belgium.
NATO’s essential purpose is to safeguard the freedom and security of its members through political and military means.
POLITICAL – NATO promotes democratic values and encourages consultation and cooperation on defence and security issues to build trust and, in the long run, prevent conflict.
MILITARY – NATO is committed to the peaceful resolution of disputes. If diplomatic efforts fail, it has the military capacity needed to undertake crisis-management operations. These are carried out under Article 5 of the Washington Treaty – NATO’s founding treaty – or under a UN mandate, alone or in cooperation with other countries and international organizations.
NATO is committed to the principle that an attack against one or several members is considered as an attack against all. This is the principle of collective defence, which is enshrined in Article 5 of the Washington Treaty. So far, Article 5 has been invoked once – in response to the 9/11 terrorist attacks in the United States.