Exponation of different missiles at the territory of the White Sands Missile Museum with a MIM-14 Nike Hercules nuclear missile in the center.
MIM-14 Nike Hercules nuclear missile at the White Sands Missile Range Museum, New Mexico. | Foto: Kelly Michals via flickr | CC BY-NC-ND 2.0

A Stress Test of Nuclear Deterrence

This month, the Tenth Review Conference of the Non-Proliferation Treaty (NPT) is taking place in New York City. The meeting of states parties, postponed four times because of the Covid pandemic, had originally been scheduled for April 2020. With Russia’s war of aggression against Ukraine, the geopolitical context has since deteriorated to the point where progress on nuclear disarmament and nonproliferation seems almost impossible. The war and Russia’s nuclear threats are fostering a renaissance of nuclear deterrence and rearmament and are threatening to deepen pre-existing fissures in the NPT. To counter the looming erosion of this cornerstone of global arms control, we need to acknowledge the darker side of nuclear deterrence that the Ukraine war is exposing. Understanding the current crisis as a crisis of nuclear deterrence can open up opportunities for de-escalation, disarmament and arms control – similar to the transformative effects of the Cuban Missile Crisis during the Cold War.

NPT in a Long-Term Crisis

Despite its overall positive track record, the NPT has also been plagued by disputes and crises since it was signed in 1968. These crises have included regional proliferation crises North Korea and Iran pushed ahead with nuclear armament even though they had ratified the NPT – but also a lack of substantial progress on nuclear disarmament: During the Cold War, especially in the 1980s, nuclear powers expanded their arsenals dramatically. Although the arsenals were subsequently reduced again, the number of warheads remained very high (currently estimated at 12,705 warheads worldwide). For this reason, the indefinite extension of the original 25-year treaty was almost in danger of collapse in 1995. Today, all NPT-recognized nuclear weapon states are pursuing comprehensive modernization programs of their arsenals and developing new delivery systems. Some – China and the United Kingdom – are even increasing the number of their warheads.

The War in Ukraine as a Stress Test

Russia’s war of aggression against Ukraine exacerbates these problems. In the view of many Western policymakers and commentators, the events since February 24 demonstrate the reliability of nuclear deterrence. After all, they argue, the West is not directly intervening in Russia’s war. Others doubt the credibility of NATO’s nuclear deterrent and believe its weakness has emboldened Russia’s aggressive behavior. Both assessments result in calls for nuclear (re)armament. In Germany, for the first time, a majority of the population supports NATO’s nuclear sharing and deterrence policy.

At the same time, the war could lead to an aggravation and multiplication of regional proliferation crises. An argument that is often advanced in social networks and media commentary holds that the Russian war of aggression against Ukraine would not have taken place if Ukraine had possessed nuclear weapons. In fact, Ukraine has never had the command over the arsenal stationed on its territory after the collapse of the Soviet Union. Nevertheless, nuclear weapons have become more attractive to some states in light of the Russian invasion. The breach of the Budapest Memorandum has shaken confidence in negative security guarantees.

The Crisis of Deterrence

For nuclear-weapon states and their allies, the mutual threat of total annihilation serves to prevent wars and thus guarantee peace and security. In the current crisis, however, it is above all the downsides of nuclear deterrence that are becoming visible. In the war against Ukraine, Russia is taking the nuclear threat to the extreme by deliberately using nuclear weapons to facilitate war. Instead of employing its nuclear arsenal to defend or prevent conventional military escalation, Moscow uses nuclear threats to increase the chances of a favorable outcome of the war and to hedge its imperialist aspirations. This undermines both the UN Charter’s prohibition of the use of force and the right to individual and collective self-defense.

In 1985 and early 2021, the U.S. and Soviet respectively Russian presidents declared that a nuclear war cannot be won and must therefore never be fought. However, the understanding of nuclear weapons as a last resort in the event of a nuclear attack has long ceased to be shared by all nuclear powers. Tactical nuclear weapons and scenarios of “limited” nuclear warfare have long been gaining importance for Russia – but also for the United States. This broadening of nuclear deterrence, as demonstrated by Russia’s threatening posturing, challenges the nuclear taboo that nuclear doctrines are supposed to reinforce. This reveals a paradox of nuclear deterrence: the more it is used and the broader nuclear threats are framed, the higher the likelihood of a nuclear escalation.

At present, NATO and Russia have a mutual interest in not extending the war beyond Ukraine’s borders. However, if Moscow fears comprehensive defeat as the war progresses, it could resort to the use of tactical nuclear weapons. The Ukraine war exposes the fragility of nuclear deterrence. After all, in the absence of the necessary common understanding of the conditions under which nuclear weapons would be used, their predictability is lost.

Reducing the Risks of Deterrence

What does all this mean for the NPT Review Conference? As the 191 NPT member states gather in New York, they will do so in the long shadow cast by the war in faraway Ukraine. And yet, it is also worthwhile for delegates to look back into the past: the “Cuban Missile Crisis” nearly 60 years ago was, like the Ukraine war, a stress test of nuclear deterrence. In the fall of 1962, the deployment of Soviet medium-range missiles in Cuba and the subsequent U.S. naval blockade brought the world to the brink of nuclear war. After 13 days, the crisis ended with the withdrawal of Soviet nuclear weapons in return for U.S. concessions (both public and private). At that time, too, Western analysts and policymakers viewed the crisis and its outcome as evidence that (U.S.) nuclear deterrence was working. Then, too, it was used to justify nuclear arms buildup.

Nevertheless, the Cuban Missile Crisis also became a “transformative event,” that was crucial in shaping confidence-building and risk-reduction measures between the two nuclear powers. These included the establishment of direct contacts at the highest military and political levels, as well as dialogues on strategic stability. At the global level, Russia and the United States cooperated to keep the nuclear order stable, admittedly to their advantage. Examples of this were the expansion of the role of the International Atomic Energy Agency – and the very NPT whose members are meeting in New York in August 2022.

The Ukraine war also holds such a transformative potential if the dangers of escalation arising from nuclear deterrence are taken seriously. The Biden administrations and NATO’s de-escalating signaling were steps in the right direction. Also, the use of highest military contact points to avoid misperceptions have thus far helped prevent an unintended expansion or even nuclear escalation of the Ukraine war. These risk reduction efforts need to be further strengthened and consolidated – including within the NPT framework.

The US, France, the UK, and their allies should take the initiative at the Review Conference to strengthen the nuclear taboo. The most convincing step they could take would be a joint declaration to renounce first use, coupled with a legally binding international commitment not to launch nuclear attacks against states that are parties to the NPT and the Treaty on the Prohibition of Nuclear Weapons or a nuclear-weapon-free zone. Reducing deterrence to a minimum – nuclear defense in the event of a nuclear attack – is necessary to end the risky blurring of deterrence of recent years. Since a NATO first-use is likely to be ruled out anyway, a public declaration would not mean a loss of military options. Rather, it would allow the West to forge an anti-nuclear war alliance on a global scale without forcing other states to take sides in the ongoing war.

Other major powers (China, India, Brazil, South Africa) and numerous non-nuclear-weapon states support a policy of nuclear restraint, but do not want to be drawn into a new East-West conflict. A broad alliance against the use of nuclear weapons could increase pressure on Russia to refrain from further nuclear threats so as not to isolate itself. At the same time, the Western nuclear-weapon states should restore the confidence in negative security guarantees destroyed by Russia and thus bolster the nuclear nonproliferation regime.


This article is an English translation of an article that has first been published on August 11, 2022 at the platform ipg-journal and on August 15, 2022 on PRIF Blog.

Caroline Fehl

Caroline Fehl

Dr. Caroline Fehl ist wissenschaftliche Mitarbeiterin im Programmbereich "Internationale Sicherheit" an der HSFK. Ihre Forschung konzentriert sich auf internationale Normen, Institutionen und Organisationen im Bereich der Rüstungskontrolle, Völkerrecht und internationale Strafjustiz. // Dr. Caroline Fehl is Senior Research Fellow at the PRIF Research Department “International Security”. Her research focuses on international norms, institutions and organizations in the fields of arms control, humanitarian law and international criminal justice. | Twitter: @CarolineFehl
Maren Vieluf

Maren Vieluf

Maren Vieluf ist wissenschaftliche Mitarbeiterin im Projekt Challenges to Deep Cuts am Berliner Büro des Instituts für Friedensforschung und Sicherheitspolitik an der Universität Hamburg (IFSH). Sie forscht dort zu Rüstungskontrolle und Abrüstung von Atomwaffen. // Maren Vieluf is a researcher in the Challenges to Deep Cuts project at the Berlin office of the Institute for Peace Research and Security Policy at the University of Hamburg (IFSH). Her research focuses on arms control and disarmament of nuclear weapons. | Twitter: @MarenVieluf
Sascha Hach

Sascha Hach

Sascha Hach ist Doktorand im Programmbereich „Internationale Sicherheit“ an der HSFK. In seiner Forschung beschäftigt er sich mit Abrüstung und Rüstungskontrolle, Nuklearwaffen, Deutscher Außenpolitik sowie den Vereinten Nationen. // Sascha Hach is a doctoral researcher in PRIF’s research department “International Security”. His research interests include disarmament and arms control, nuclear weapons, German Foreign Policy and the United Nations.

Caroline Fehl

Dr. Caroline Fehl ist wissenschaftliche Mitarbeiterin im Programmbereich "Internationale Sicherheit" an der HSFK. Ihre Forschung konzentriert sich auf internationale Normen, Institutionen und Organisationen im Bereich der Rüstungskontrolle, Völkerrecht und internationale Strafjustiz. // Dr. Caroline Fehl is Senior Research Fellow at the PRIF Research Department “International Security”. Her research focuses on international norms, institutions and organizations in the fields of arms control, humanitarian law and international criminal justice. | Twitter: @CarolineFehl

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