This article is a general, nonpartisan explainer. It describes the United States unless stated otherwise, and details change over time, so check official sources for the latest.
The North Atlantic Treaty Organization was founded in 1949 with the signing of the North Atlantic Treaty in Washington. Its membership has grown over time and, following the accessions of Finland in 2023 and Sweden in 2024, includes 32 countries.
Collective defense
Article 5 of the treaty says that an armed attack against one member is considered an attack against all. It has been formally invoked once, after the attacks of September 11, 2001. Each member decides what action it considers necessary.
Political structure
- North Atlantic Council: the main decision-making body, where each member has a seat.
- Consensus: decisions are taken by agreement, not by majority vote.
- Secretary General: chairs meetings and speaks for the alliance.
Military structure
NATO has an integrated command structure led by the Supreme Allied Commander Europe, who is traditionally an American officer. Forces mostly remain under national command and are placed under NATO command for specific missions.
Areas of work
- Deterrence and defense.
- Crisis management and operations.
- Partnerships with other countries and organizations.
- Capability development and standards.
Challenges
Consensus decision-making can be slow. Members also differ in threat perceptions and spending. These issues are regularly discussed at summits.
For current figures and commitments, consult NATO’s official website.
