North Atlantic Treaty OrganizationInternational

The North Atlantic Treaty Organization (NATO) is an intergovernmental political and military alliance of North American and European nations headquartered in Brussels, Belgium. Its primary mandate is to guarantee the freedom and security of its members through political consultation and mutual defense under Article 5 of the Washington Treaty. Established in the aftermath of World War II to counter Soviet expansion, NATO historically invoked Article 5 for the first and only time following the September 11 terrorist attacks in 2001.