NATO (North Atlantic Treaty Organization)

NATO was established in the immediate aftermath of the Second World War to bind the United States, Canada, and the democracies of Western Europe into a permanent security community. Its founding treaty was signed in Washington, D.C., on April 4, 1949, by twelve original member states. The organization has its political headquarters in Brussels, Belgium, and its military nerve center, the Supreme Headquarters Allied Powers Europe (SHAPE), at Mons in southern Belgium. Membership has grown in ten successive waves of enlargement to thirty-two states, most recently with the accession of Finland in 2023 and Sweden in 2024.

The alliance is governed by consensus among the member states through the North Atlantic Council, chaired by the Secretary General, a senior civilian diplomat chosen by common agreement of the allies. The Military Committee, composed of the chiefs of defense of the member states, provides military advice to the council and directs the work of NATO's two strategic commands: Allied Command Operations, led from SHAPE by the Supreme Allied Commander Europe, and Allied Command Transformation, led from Norfolk, Virginia, by the Supreme Allied Commander Transformation. National armed forces remain under national control in peacetime but are trained, exercised, and, where necessary, employed together under NATO command.

Although NATO was created as a defensive alliance and its founding treaty describes a limited geographic area of application, its activities now extend well beyond the territory of its members. The alliance has undertaken operations in Kosovo, Afghanistan, the Mediterranean Sea, off the Horn of Africa, and in Iraq, and it maintains partnerships with more than forty countries around the world, including dialogue with neighbors in the Mediterranean, Middle East, and Indo-Pacific. Since the full-scale Russian invasion of Ukraine in February 2022, the alliance has returned to its core deterrence and defense mission with renewed intensity, reinforcing its eastern flank and revising its strategic concept.