What is NATO?
The North Atlantic Treaty Organisation (NATO) was created in 1949 with the signing of the North Atlantic Treaty in Washington, USA. Then, it was an alliance of ten European states including the UK, and America and Canada. The post-war Labour Government, led by Clement Attlee, saw the Soviet Union as a significant threat to Western democracies, and believed a new, international alliance was the best, enduring instrument of peace.
Article 5 of the NATO treaty states that:
“The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.
Any such armed attack and all measures taken as a result thereof shall immediately be reported to the Security Council. Such measures shall be terminated when the Security Council has taken the measures necessary to restore and maintain international peace and security.”
This makes it clear that NATO is a defensive alliance, based on a collective response if its members in Europe or North America come under attack. That is why the only time Article 5 has been invoked is the day after the USA came under attack on 9/11.
Today NATO is an alliance of 32 countries, including the former Warsaw Pact countries after the collapse of Soviet communism, and the accession of seven more countries in 2004 including the Baltic states. After Putin’s invasion of Ukraine in 2022, Finland and Sweden, joined NATO.
The Ankara Declaration
July 2026
Most recently, NATO leaders, including Sir Keir Starmer, met in Ankara and issued the following declaration:
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We, the Heads of State and Government of the North Atlantic Alliance, have gathered in Ankara to reaffirm our ironclad commitment to our collective defence under Article 5 of the Washington Treaty and to the transatlantic bond. An attack on one is an attack on all. Our unity, solidarity and collective strength remain the foundation of peace, security, and prosperity for the one billion citizens in our Alliance of free and democratic nations. We remain committed to our 360-degree approach to deterrence and defence.
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To counter the long-term threat Russia poses to Euro-Atlantic security and stability, and the persistent threat of terrorism, Allies are delivering on The Hague defence commitment. In 2025, European Allies and Canada increased their investments in core defence requirements by more than $139 billion. Our investments are delivering the capabilities we need while strengthening our industrial base and resilience. Today in Ankara, we announce more than $50 billion in new procurements and commit to expanding collective manufacturing capacity and working with industry to accelerate innovation. We will continue our work to eliminate defence trade barriers among Allies and leverage NATO’s partnerships to maximise defence industrial depth and cooperation.
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We are building the future: a stronger Europe in a stronger NATO – a modernised Alliance. European Allies and Canada, working with the United States, are assuming greater responsibility for the Alliance’s defence. NATO’s deterrence and defence rest on an appropriate mix of nuclear, conventional, and missile defence capabilities, complemented by space and cyber assets. We are committed to maintaining our combat advantage. We are investing in our ability to deploy, enable and sustain our armed forces and deliver our capability targets in all domains, including in deep precision strike, integrated air and missile defence, uncrewed systems, cutting edge technologies, and intelligence capabilities. We are developing an interoperable transatlantic warfighting cloud and adopting powerful AI models.
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Ukraine contributes to transatlantic security, and Allies stand united in our unwavering support for Ukraine in defending its freedom, sovereignty, and territorial integrity. European Allies and Canada now finance the vast majority of security assistance to Ukraine through bilateral and multilateral means. Allies underscore that this support must be equitable, predictable, and sustainable in the long-term. For 2026, Allies pledge €70 billion in military equipment, assistance and training for Ukraine and affirm their sovereign commitments to sustaining at least equivalent levels in 2027. To this end, we welcome the European Union’s decision to provide multi-year funding to Ukraine through the Ukraine Support Loan.
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The Alliance continues to respond and adapt to the strategic competition, pervasive instability, hybrid threats and recurrent shocks that define our broader security environment. Allies reiterate that Iran must never have a nuclear weapon and call on Iran to fully respect freedom of navigation in the Strait of Hormuz.