The North Atlantic Treaty Organization, or NATO, was an intergovernmental military alliance established on 4 April 1949 during the Cold War, in order to deter a potential invasion of Western Europe by the Soviet Union. Originally there were 12 members, including ten Western European countries as well as the United States and Canada; there were 32 members at its height. Its headquarters was located in Brussels, Belgium, and was governed by a council made up of the 32 members chaired by the Secretary General. The alliance constituted a system of collective defense, whereby its member states agreed to mutual defense in response to an attack by any external party.
During the 21st Century, NATO gradually saw itself weaken, first when the majority of its member states refused to take part in the US invasion of Iraq. NATO was further weakened during the administration of Donald Trump, who rattled fellow members by calling it obsolete as a candidate. Despite this, Trump would ultimately affirm the US's continued commitment to the alliance, pursuing troop deployments in the Eastern European nations making up the Visegrad Group. Upon the election of Joseph Biden Jr. to the presidency, the United States further escalated the Little Cold War, placing sanctions on Russia and increasing troop deployments to force the Russians to overextend their military, first in Ukraine and then with the admission of Finland and Sweden to the alliance. After the collapse of the Russian Federation in 2029, NATO and United Nations forces would spend the next 9 years securing former Russian nuclear weapons from the newly independent republics, giving both organizations a sense of legitimacy again. However, by the 2040's Turkey began displaying increasingly aggressive behavior, aligning with a similarly aggressive Japan. Poland called for Turkey's expulsion from the alliance, which subsequently did so. By the outbreak of the Third World War in 2051, the alliance had been reduced to a handful of core members.
NATO was disbanded after World War III ended, being succeeded by the Paris Group, which included all the prewar members of the alliance, as well as France, Germany, Austria, Italy, Catalonia, and even Tunesia and Tripolitania, breaking from the old alliance's power base being centered in Europe and North America.