Article 5 of the Washington Treaty

NATO is primarily a defensive military organisation. At the heart of this lies Article 5 of the Washington Treaty. This is the famous article that means an attack against one member is considered an attack against all.

NATO does not have its own army, navy or air force. All Allies are expected to be willing and able to contribute to NATO Operations. NATO has only evoked Article 5 once during its 60 year history, and that was in the immediate aftermath of the tragic events of 11 September 2001.