NATO: History, Structure and Missions

Posted on Feb 13, 2026 in History

NATO: History, Structure and Missions

Created in 1949, at the beginning of the Cold War. The Washington Treaty established the alliance. 29 members (Europe and North America). Type: Military Alliance. NATO organizes regular summits for leaders of its member states and partnerships.

Founding and Cold War Era

1st period (1949–1989): Enemy: Warsaw Pact (1955). This military alliance was led by the Soviet Union. In 1966, Charles de Gaulle decided to withdraw from NATO’s integrated military command. During the Cold War, there was no direct military confrontation. After the Cold War, or after the fall of the Berlin Wall in 1989, new memberships entered the Alliance. During the Cold War, NATO confronted the Soviet Union’s threat; nowadays, it fights against terrorism, including ISIS.

Membership Numbers

There are 12 founding countries and 17 nations that joined the treaty after. Twelve are original members who joined in 1949, while the other 17 joined in one of the eight enlargement rounds.

Enlargements

Enlargements:

  • 1982: Spain
  • 1999: Hungary, Poland, Czech Republic
  • 2004: Bulgaria, Slovakia, Slovenia, Estonia, Lithuania, Latvia, Romania
  • 2009: Croatia and Albania
  • 2017: Montenegro

Responsibilities and Article 5

Currently, the great responsibility of the Alliance is to protect and defend NATO’s territory and population. Article 5 of NATO’s founding charter, the Washington Treaty, sets out the Alliance’s collective defence commitment, stating that an attack on one shall be considered an attack on all. Article 5 was invoked for the first time with the 11 September (9/11) terrorist attacks.

Military Operations and Post–Cold War Actions

No military operations occurred during the Cold War. The first operations happened after the Cold War. An early NATO intervention was in 1994; air strikes helped bring the Yugoslav wars to an end, resulting in the Dayton Agreement in November 1995.

Structure

Structure:

  1. North Atlantic Council (NAC):

    The NAC is the main political decision-making body within NATO. Each member country has a seat at the NAC. The NAC brings together high-level representatives of each member country to discuss policy or operational questions requiring collective decisions.

  2. General Secretary:

    Jens Stoltenberg since 2009. The General Secretary is responsible for steering the process of consultation and decision-making within the Alliance and ensuring that decisions are implemented.

  3. Military Committee:

    This institution is composed of the Chiefs of Defence of NATO member countries; its executive body, the International Military Staff, and the Military Command Structure.

NATO does not have its own troops. When an operation is agreed by the NAC, members contribute forces on a voluntary basis. These forces return to their countries once the mission is completed.

NATO’s Three Core Tasks

  • Collective Defence: an attack on one member is an attack on all;
  • Crisis Management;
  • Cooperative Security.

Operations: Kosovo and Afghanistan

1) Kosovo: NATO KFOR mission was to contribute to maintaining a safe and secure environment as mandated by the United Nations Security Council.

2) Afghanistan: From 2003 to 2018, the NATO-led International Security Assistance Force (ISAF), authorized by the UN, conducted a peacekeeping mission that provided training, assistance and support to the people of Afghanistan to take their future back into their hands. Spanish soldiers participated in ISAF.

Cooperative Security and Partnerships

Cooperative Security Partnerships:

  • Over the past two decades, NATO has developed a network of structured partnerships with countries from the Euro-Atlantic area and the Mediterranean and Gulf regions, as well as individual relationships with other partners across the globe.
  • NATO pursues dialogue and practical cooperation with more than 40 partner countries and engages actively with other international actors and organizations.
  • Among these partners, NATO has developed specific structures for its relationships with Georgia, Russia and Ukraine.
  • Due to Russia’s aggressive actions in Ukraine and its illegal actions in Crimea, NATO suspended its practical cooperation with Russia in early 2014.
  • The EU is a unique and essential partner for NATO. The organizations share common values, strategic interests and 22 common member states.