Deterrence and defence
NATO is a defensive alliance whose members are committed to safeguarding the freedom and security of all Allies, against all threats, from all directions. Deterrence and defence is one of NATO’s core tasks. The Alliance deters aggression by maintaining a credible deterrence and defence posture based on an appropriate mix of nuclear, conventional and missile defence capabilities, complemented by space and cyber capabilities. Allies are significantly strengthening the deterrence and defence of the Alliance as the backbone to their Article 5 commitment to defend each other.

The USS Gerald R. Ford sails out of the Oslo Fjord in Norway in May 2023. (Photo: Norwegian Armed Forces)
- Russia’s war of aggression against Ukraine poses the gravest threat to Euro-Atlantic security in decades, shattering peace in Europe and reinforcing the need for NATO to ensure that its deterrence and defence posture remains credible and effective.
- In response, NATO has activated its defence plans, deployed elements of the NATO Response Force and significantly increased the number of forces on its eastern flank.
- On 24 March 2022, at an extraordinary summit, NATO Leaders agreed to deploy four battalions in Bulgaria, Hungary, Romania and Slovakia, in addition to the four already present in Estonia, Latvia, Lithuania and Poland.
- At the Madrid Summit in June 2022, NATO Leaders approved a new Strategic Concept, which describes the security environment facing the Alliance and identifies NATO’s core tasks. The Strategic Concept states that Russia is the most significant and direct threat to Allies’ security and to peace and stability in the Euro-Atlantic area. It also states that terrorism, in all its forms and manifestations, is the most direct asymmetric threat to the security of the Alliance’s citizens and to international peace and prosperity.
- At the Madrid Summit, Allies also committed to deploying additional robust, in-place, combat-ready forces to NATO’s eastern flank, to be scaled up from the existing battalion-sized battlegroups to brigade-size units, where and when required, and to ensure these forces will be underpinned by credible, rapidly available reinforcements, prepositioned equipment, and enhanced command and control. Allies agreed a new force model, which strengthens and modernises the NATO Force Structure and supports NATO’s core tasks and new generation of military plans.
- NATO Leaders built upon these decisions at the 2023 Vilnius Summit, where they approved a new generation of regional defence plans, a new multinational and multi-domain Allied Reaction Force, and a new rotational model of modern air defence systems and capabilities.
- Two military concepts set the direction for NATO’s ongoing adaptation: the Concept for Deterrence and Defence of the Euro-Atlantic Area focuses on force employment to deter and defend today, while the NATO Warfighting Capstone Concept offers a vision to guide the Alliance’s long-term warfare development to remain militarily strong now and in the future.
- Allies have made considerable progress in increasing defence spending and investing in major equipment, taking steps towards fairer burden-sharing within NATO. Since 2014, European Allies and Canada have invested an extra USD 450 billion in defence, with the latest estimates showing an increase of 8.3% in 2023.
- A rapidly changing security environment
- Safeguarding the freedom and security of NATO’s members
- Resilience: the first line of deterrence and defence
- Bolstering NATO's readiness, responsiveness and reinforcement
- Maintaining the Alliance's military and technological edge
- Investing in defence
A rapidly changing security environment
NATO faces the most complex security environment since the end of the Cold War. Russia's war of aggression against Ukraine is jeopardising European security, and terrorism continues to represent a global security challenge and a threat to stability. At the same time, China’s stated ambitions and coercive policies challenge the Alliance's interests, security and values. Growing global uncertainty, more sophisticated and disruptive cyber and hybrid threats, and exponential technological change are having a substantial impact on the Alliance.
Russia's war of aggression against Ukraine has shattered peace in Europe and is causing enormous human suffering and destruction. Russia is the most significant and direct threat to Allies’ security and to peace and stability in the Euro-Atlantic area. Its coercive military posture, rhetoric and proven willingness to use force to pursue its political goals undermine the rules-based international order. Terrorism, in all its forms and manifestations, is the most direct asymmetric threat to the security of NATO citizens and to international peace and prosperity. Conflict, fragility and instability in Africa and the Middle East directly affect the security of the Alliance and its partners. NATO’s southern neighbourhood, particularly the Middle East, North Africa and Sahel regions, faces interconnected security, demographic, economic and political challenges. These are aggravated by the impact of climate change, fragile institutions, health emergencies and food insecurity.
Safeguarding the freedom and security of NATO’s members
NATO's essential and enduring purpose is to safeguard the freedom and security of all its members by political and military means. Collective defence is at the heart of the Alliance, as set out in Article 5 of the North Atlantic Treaty. NATO's greatest responsibility is to protect and defend Allied territory and populations against attack in a world where peace and security cannot be taken for granted.
Deterrence is a core element of NATO's overall strategy: preventing conflict and war, protecting Allies, maintaining freedom of decision and action, and upholding the principles and values it stands for – individual liberty, democracy, human rights and the rule of law. Free societies and the rules-based international order need to be backed by credible transatlantic defence.
At the 2022 Madrid Summit, NATO set a new baseline for its deterrence and defence posture in line with its 360-degree approach, across the land, air, maritime, cyber and space domains, and against all threats and challenges.
NATO’s deterrence and defence posture is based on an appropriate mix of nuclear, conventional and missile defence capabilities, complemented by space and cyber capabilities. NATO maintains the freedom of action and flexibility to respond to the full spectrum of challenges with an appropriate and tailored approach.
Resilience: the first line of deterrence and defence
Enhancing resilience by strengthening the capacity of societies to prepare for, respond to, recover from and adapt to the full range of threats and hazards is an integral part of NATO's deterrence and defence posture. Russia’s war against Ukraine, growing geopolitical competition and the many other security challenges faced by the Alliance today underscore the importance of NATO’s “all hazards” and “whole of society” approach to resilience. By preparing, empowering and investing in the ability of societies to defend themselves against a wide range of threats – from cyber attacks to chemical, biological, radiological and nuclear incidents, terrorism, pandemics and natural disasters – Allies address vulnerabilities that can otherwise be used as leverage or be targeted by adversaries. Resilience is therefore an important aspect of deterrence by denial: persuading an adversary not to attack by convincing it that an attack will not achieve its intended objectives.
Resilience also requires close civil-military cooperation, as it impacts NATO's ability to conduct its missions and maintain the mobility of troops and equipment. Ensuring that national and military forces under NATO command are adequately supported with civilian resources and infrastructure is a core feature of NATO’s resilience efforts. Since 2014, NATO has been providing guidelines to assist national authorities in improving their resilience across seven baseline requirements by reducing potential vulnerabilities. These requirements are updated regularly to reflect the evolving nature of the challenges faced by the Alliance.
In line with the NATO 2030 agenda and the 2021 Strengthened Resilience Commitment, the 2022 Strategic Concept stresses the importance of adopting a more integrated and better coordinated approach to resilience within the Alliance, including against Russian coercion, and in supporting NATO partners to counter malign interference and aggression. Partnerships with non-NATO countries and other organisations are essential to reinforce Allies’ national and collective resilience, and to support the Alliance’s planning and preparedness through the sharing of information and best practices.
Bolstering NATO's readiness, responsiveness and reinforcement
The Readiness Action Plan (RAP), launched at the Wales Summit in 2014, was a major driver for change in the Alliance's deterrence and defence posture. The RAP included assurance measures for NATO Allies in Central and Eastern Europe to reassure their populations, deter potential aggression and reinforce their defence.
Building on the RAP, NATO Heads of State and Government approved a strengthened deterrence and defence posture at the Warsaw Summit in 2016. It provided the Alliance with a broad range of options to be able to respond to any threats from wherever they arise to protect NATO territory, populations, airspace and sea lines of communication. Allies agreed to establish an enhanced Forward Presence in the eastern part of the Alliance, and in 2017 four NATO multinational battlegroups were deployed in Estonia, Latvia, Lithuania and Poland. Additional measures were taken to reinforce security in the south-east of the Alliance, with a tailored Forward Presence in the Black Sea region. Furthermore, a number of measures have been undertaken to adapt the Alliance to the challenges emanating from the South, including capacity-building, dedicated exercises and advance planning, as well as setting up the Regional Hub for the South in Naples, Italy, which contributes to NATO's situational awareness.
Exercises remain an integral part of NATO's deterrence and defence posture since military training is an essential requirement to maintain the Alliance's readiness levels and improve interoperability.
NATO's adaptation efforts continue in all domains and in areas such as civil preparedness and countering hybrid threats, including in cooperation with the European Union (EU). Relations with the EU include increased cooperation, as well as complementary and interoperable capability development to avoid duplication and contribute to transatlantic burden-sharing.
At the 2018 Brussels Summit, NATO Leaders reiterated their resolve to bolster the Alliance's readiness, responsiveness and reinforcement to respond to threats from any direction in a 360-degree approach. A NATO Readiness Initiative was launched to enhance the Alliance's rapid-response capability, either for reinforcement of Allies in support of deterrence or collective defence, including for high-intensity warfighting, or for rapid military crisis response, if required. It consisted of providing 30 heavy or medium manoeuvre battalions, 30 kinetic air squadrons and 30 major naval combatants at 30 days’ readiness or less. These forces are being organised and trained as larger combat formations.
NATO has recognised cyberspace as a domain of operations in which it must defend itself as effectively as it does in the air, on land and at sea. The creation of a Cyberspace Operations Centre in Belgium in 2018 and the formation of counter-hybrid support teams to assist Allies in need also bolster the Alliance's deterrence efforts. At the 2021 Brussels Summit, Allies endorsed a new Comprehensive Cyber Defence Policy, which supports NATO’s core tasks and overall deterrence and defence posture to enhance the Alliance’s resilience in cyberspace.
NATO continues to address the security implications of Russia's growing arsenal of nuclear-capable missiles, which poses a significant risk to Alliance security. The Alliance is responding by strengthening its advanced conventional capabilities, investing in new platforms – including fifth-generation fighter aircraft – and adapting its exercises, intelligence, and air and missile defence posture. It is doing so while ensuring its nuclear deterrent remains safe, secure and effective. At the same time, NATO remains strongly committed to effective arms control, disarmament and non-proliferation, and continues to call for all actors, including Russia and China, to engage constructively.
At the December 2019 Leaders' Meeting in London, NATO declared space as a fifth operational domain. The information gathered and delivered through satellites is critical for NATO activities, operations and missions, including collective defence, crisis response and counter-terrorism. The NATO Space Centre established in 2020 in Germany serves as a focal point for sharing information, coordinating Allies' efforts and supporting NATO's operations and missions. At the 2021 Brussels Summit, NATO recognised that attacks to, from or within space present a clear challenge to the security of the Alliance and could lead to the invocation of Article 5 of the North Atlantic Treaty.
NATO Leaders met in Brussels on 24 March 2022 to address the consequences of Russia’s brutal and unprovoked war of aggression on Ukraine and to take measures to strengthen NATO’s deterrence and defence. They decided to deploy four multinational battlegroups in Bulgaria, Hungary, Romania and Slovakia, in addition to those already present in Estonia, Latvia, Lithuania and Poland, effectively doubling the number of battlegroups on NATO’s eastern flank from four to eight. They also decided to step up cyber defences and scale up exercises focused on collective defence and interoperability.
At the Madrid Summit in June 2022, NATO Leaders made decisions to significantly strengthen the Alliance’s deterrence and defence posture. To that end, Allies agreed to adjust the balance between in-place forces and reinforcement, and committed to deploying additional robust, in-place, combat-ready forces on NATO’s eastern flank, to be scaled up from the existing battalion-sized battlegroups to brigades, where and when required, underpinned by credible rapidly available reinforcements, prepositioned equipment, and enhanced command and control. This strengthens deterrence and supports the ability to defend forward. Allies also agreed a new force model, which strengthens and modernises the NATO Force Structure, supports the Alliance’s core tasks and resources its new generation of military plans. Allies agreed to ensure a substantial and persistent presence on land, at sea and in the air, including through strengthened integrated air and missile defence.
At the 2023 Vilnius Summit, NATO Leaders approved the Alliance’s most comprehensive and detailed defence plans since the Cold War. This new generation of regional defence plans will significantly improve the coherence of NATO’s collective defence planning with Allies’ national planning of their forces, posture, capabilities, and command and control. In order to ensure the effectiveness of these plans, Allies are delivering a larger pool of dedicated combat-capable forces, harnessing regional expertise and geographic proximity to improve military responsiveness. They are also establishing a new multinational and multi-domain Allied Reaction Force, which will provide more options to respond swiftly to threats and crises in all directions. NATO Leaders also agreed to strengthen NATO’s command and control, and welcomed ongoing efforts by Allies to increase their presence on NATO’s eastern flank. NATO Leaders agreed to improve the readiness, preparedness and interoperability of NATO’s Integrated Air and Missile Defence, in particular through the regular training and rotational presence of modern air defence systems and capabilities across NATO territory in Europe, with an initial focus on the Alliance’s eastern flank.
Maintaining the Alliance's military and technological edge
While the Alliance needs to be able to preserve peace today, it also needs to prepare for the increasingly unpredictable security environment of the future. To this end, at the Brussels Summit in June 2021, Allied Leaders agreed to the full implementation of the NATO Warfighting Capstone Concept, which supports having a more proactive and anticipatory approach to military adaptation. Keeping its technological edge has always been an essential enabler of NATO's ability to deter and defend against potential adversaries. Innovations in emerging and disruptive technologies such as artificial intelligence, autonomous weapons systems, big data and biotech are changing warfare. To help preserve its technological edge, NATO has agreed an implementation strategy for emerging and disruptive technologies. It also established a Defence Innovation Accelerator for the North Atlantic (DIANA) and, at the Madrid Summit in June 2022, launched a multinational Innovation Fund, bringing together governments, the private sector and academia to bolster NATO’s technological edge. The Alliance will play an important role as a forum for cooperation on various security-related aspects of these emerging technologies.
Investing in defence
The Defence Investment Pledge, adopted by NATO Leaders at the 2014 Wales Summit, called for all Allies to stop cuts to defence budgets and move towards the NATO-agreed guideline of spending at least 2% of Gross Domestic Product (GDP) on defence within a decade. Allies also agreed, in that same timeframe, to move towards spending at least 20% of annual defence expenditure on new major equipment and related research and development. Since then, Allies have all increased their defence spending, further developed their forces and capabilities, and have contributed to Allied operations, missions and activities. The latest estimates show that defence expenditure by European Allies and Canada will increase by 8.3% in 2023, marking the ninth consecutive year of increased defence spending by these countries, with a cumulative investment of almost USD 450 billion extra in real terms since 2014.
At the 2023 Vilnius Summit, NATO Leaders agreed a new Defence Investment Pledge, making an enduring commitment to invest at least 2% of Gross Domestic Product (GDP) annually on defence. They also affirmed that in many cases, expenditure beyond 2% of GDP will be needed in order to remedy existing shortfalls and meet the requirements across all domains arising from a more contested security order. NATO Leaders committed to invest at least 20% of their defence budgets on major equipment and related research and development; this investment in major equipment should be met in conjunction with a minimum of 2% of GDP annual defence expenditure. Allies also committed to contribute the necessary forces, capabilities and resources to the full range of NATO operations, missions and activities.