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For decades, U.S. and NATO officials have emphasized that nuclear weapons helped to sustain peace. Less than two years ago, NATO Secretary General Jens Stoltenberg stressed that “in an uncertain world, [nuclear] weapons continue to play a vital role in preserving peace.”[1] However, the Russian incursion into Ukraine, Vladimir Putin’s repeated nuclear threats, and growing concern about a major war on the European continent between Russia and NATO have called this apparent certainty into question. Even more pressing questions have arisen concerning the injustice that comes with nuclear peace.


Peace (for the Great Powers)

At first glance, the peacekeeping function of nuclear weapons seems to be genuine. Since 1945, the major powers have abstained from large-scale conventional wars against each other. World War III has not materialized. Granted, nuclear-armed states do threaten each other, condemn each other,and impose economic sanctions on each other – but they have shied away from a major military conflict for fear of crossing the nuclear threshold. While it is impossible to establish a causal link between great power peace and the nuclear age with any scientific certainty, there at least seems to be a correlation between nuclear deterrence and (partial) peace. These well-known mechanisms would seem to still be in place and functioning well, even on the ongoing crisis.

Putin has threatened NATO, but thus far he has stopped short of initiating an open military conflict with the alliance, just as NATO has not engaged in open military conflict with Russia. The West’s nuclear weapons continue to deter Putin and Russia’s nuclear arms continue to deter NATO. Ukraine, on the other hand, stripped of all nuclear defenses, has been rendered unable to deter Russian aggression and is fighting a bloody multi-front war against the invaders.

The Cold War was likewise characterized by this paradox. While NATO and the Warsaw Pact enjoyed a precarious state of stability, built on tens of thousands of warheads, individual countries on the geographical periphery of the global conflict repeatedly experienced war and instability. At the time, Washington and Moscow interfered in these conflicts as much as possible, providing military and logistical support to the Vietcong and the Mujahideen. Meanwhile, interference in conflicts within their own spheres of influence – as with the Warsaw Pact’s crushing of the Prague Spring in 1968 – remained off limits. Escalation caused by external interference simply seemed too great a risk.

The ripple effects of the historic injustices of nuclear peace, especially toward the countries of the Global South, are still being felt today.

Whether the stability–instability paradox still determines our historically evolved approach to nuclear deterrence today will become clear in the coming weeks and months. However, there are certain indications that the emerging nuclear crisis is taking place under somewhat different auspices.


Novel Aspects of the War

First, there is the matter of geographical, and thus cultural, proximity. The war in Ukraine is taking place not in the far-off and instable lands of Asia but in the middle of Europe. The refugees are coming from a country of the western culture. The sheer fact of geographical proximity also increases the risk of an unintended military confrontation in the immediate vicinity of the Ukrainian border, where NATO and Russian troops are operating. Furthermore, the Kremlin has asserted a direct claim to Ukrainian territory, denying Ukrainian sovereignty within recognized borders. The fact that the West does not recognize this claim and instead rightly refers to the Charter of Paris of 1990,[2] which Moscow signed, constitutes a further aspect of the conflict constellation.

This struggle for power, geopolitical order, and security in direct geographic proximity are in turn raising the stakes for Russia and the West. Parallels to the Cuban Missile Crisis of 1962 have been made,[3] even though the Kennedy administration was ultimately interested in a secret reconciliation of interests back then. In return for the withdrawal of Soviet missiles from Cuba, Washington later withdrew its Jupiter nuclear missiles from Turkey and committed itself to a permanent renunciation of the use of military force against Cuba, to which consecutive U.S. administrations, including the Reagan, George W. Bush, and Trump administrations, adhered. Fast forward to today: Putin has shown no indication that he is interested in an off-ramp. Nor does he seem to be concerned about the nuclear balance. The West, meanwhile, lacks negotiating leverage as the Kremlin’s maximum demands are simply unacceptable and completely at odds with the European peace order agreed in 1990.

Finally, the war in Ukraine differs from many previous conflicts in informational aspects. While during the Cold War television and radio news broadcasts – as well as politically curated daily newspapers – focused for instance on the war in Vietnam for a limited period of time each day, in the case of Ukraine countless clips, photos, open discussion forums, and freely accessible satellite and flight data now make it possible for everyone to ‘experience’ and comment on the war on social media, seemingly in real time and 24/7. As a result, large segments of the populations of Western countries have become emotionally invested in the fate of Ukraine and its people.

In addition, these developments in information gathering have coincided with a new generation of leaders who were politically socialized in the decades following the Cold War and who now exercise significant media and political power. The members of this generation seem far more committed to normative ideals such as freedom, inclusion, and equality and are far less willing to prioritize diffuse security concepts such as nuclear deterrence over fighting clear injustices. This may partially explain repeated calls for a NATO-imposed no-fly zone over Ukraine,[4] which consciously or unconsciously ignore and belittle the Russian nuclear deterrence.


Unjust Peace

With this shift, the justice motivation has come increasingly to the fore. Is there any justice in denying Ukrainians the same level of security that we ourselves, in the nuclear-armed West, enjoy? Is there any question that NATO would have taken direct military action much earlier if Russia was not a nuclear power? What right does Putin have to enjoy the fruits of deterrence – freedom from any external military intervention – while he invades his neighbor? A realistic answer to these questions must conclude that the nuclear peace is at best a highly unjust peace insofar as it is unequally distributed. It favors old, white, wealthy societies and autocrats, nationalists, despots, and dictators – from Moscow, to New Delhi, to Beijing, to Pyongyang.

The ripple effects of the historic injustices of nuclear peace, especially toward the countries of the Global South, are still being felt today. At the 2 March Special Session of the United Nations General Assembly, 141 states voted in favor of a resolution condemning the Russian invasion and calling for Russia’s withdrawal from Ukraine. At the same time, 35 states abstained, including many African countries and both major and middle powers such as China, India, Nigeria, Pakistan, and South Africa. The British economic historian Adam Tooze observed that the combined population of all abstaining states was equivalent to 51 percent of the global population.[5] Aside from America and its allies in Europe, East Asia, and the Pacific, no other country worldwide has enacted sanctions against Russia in response to the Russian onslaught against Ukraine.

The historical injustices of nuclear peace against the countries of the Global South may very well soon be dwarfed by new injustices on a much larger scale. With Putin’s invasion of Ukraine, a Cold War 2.0 is becoming increasingly likely. For Europe, this could mean that a new Iron Curtain could soon stretch across the old continent, from Finland in the north to the Turkish Bosporus in the south. Given the deepening military-political cooperation between Moscow and Beijing, we cannot rule out the possibility of a new global bloc confrontation, with America and its allies in Europe, East Asia, and the Pacific region on one side, and China, Russia, and other potential partners (some authoritarian, e.g. Iran, and others strongly nationalistic, e.g. India) on the other. Such a bloc confrontation and concomitant conventional and nuclear arms races would absorb the urgently needed energy for jointly tackling climate change, malnutrition, and prevent future pandemics. Any realistic observer must conclude that the global community has neither the time nor the resources to fight a new Cold War.


Precarious Peace

At worst, however, nuclear peace is not only unjust but potentially a chimera. Putin’s nuclear threats, if meant as attempts to coerce the United States and its allies into changing their politics, have thus far failed to impress the West.[6] The rhetorical threats in his 24 February war speech were followed by unprecedented economic and financial sanctions and ever increasing arms deliveries to Ukraine. Putin’s 27 February order to increase the readiness of Russia’s nuclear forces was followed, among other things, by NATO member Turkey’s closure of the Bosporus Straight to certain Russian warships. The West is thus deliberately shifting the level of action to policy areas in which it can exercise power while simultaneously trusting in its ability to deter Putin from resorting to nuclear weapons. For Putin, on the other hand, coercion by nuclear means for offensive purposes could soon be one of the few remaining areas through which Russia can maintain escalation dominance. Some experienced Russia hands have warned that he will become increasingly likely to use these options the more the war in Ukraine fails to achieve his objectives and the stronger the pressure from the West.[7] President Biden’s unhelpful remarks in Warsaw regarding a regime change[8] and Washington’s edging toward a policy that pits the United States more directly against Moscow[9] may just add to that pressure.

But pressure on Putin is not the only pathway along which the current crisis could escalate to the nuclear level. The possible use of chemical weapons by Russia against the Ukrainian population, perhaps under a false flag attack, would create enormous domestic political pressure in Washington, Brussels, Warsaw and Berlin to intervene directly in Ukraine. Putin has made it abundantly clear that he considers Ukraine to be part of the historic Russian Empire – no matter how unacceptable and illegal this view is. From Putin’s perspective, military intervention involving NATO forces would likely be seen as an attack on Russia itself. In addition, in order to establish air sovereignty over Ukraine, such an intervention force would have to be prepared to do exactly that: eliminate Russian air defenses on Russian territory with targeted strikes. It would be naïve to assume that Putin would not consider using nuclear weapons in such an extreme scenario. At that point, if not sooner, the world would be on the brink of a nuclear Armageddon.


What Next?

With Ukraine’s fate in mind, other states may soon clandestinely seek out nuclear protection – some through efforts of their own, others through stronger or novel alliance arrangements. The negative fallout from the war with regard to ongoing diplomatic efforts to prevent Teheran from acquiring nuclear weapons puts Iran at the top of this list. How Taiwan – claimed by China and militarily supported by the United States – positions itself in the coming months will be decisive for peace in East Asia.

That the unchecked horizontal proliferation of nuclear arms is not a viable path was agreed upon by the international community in the 1968 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and has been reaffirmed repeatedly since then. The rationale was that the greater the number of nuclear-armed states, the higher the risk of a renewed use. In the interest of addressing nuclear injustice, the five nuclear powers officially legitimized by the United Nations under the NPT, committed themselves to complete disarmament. Despite these commitments, however, China, France, Russia, the United Kingdom, and the United States currently possess a combined total of more than 12,000 warheads. Nuclear modernization and rearmament programs have been underway in each of these states for several years. At the same time, arms control treaties have collapsed one after the other since the beginning of the new millennium – most recently the Intermediate-Range Nuclear Forces Treaty and the Open Skies Treaty. Despite a novel treaty banning nuclear weapons[10] that entered into force on 22 January 2021, the goal of complete global disarmament has become a very distant prospect, also because of Putin’s brutal war of aggression.

The bitter answer is that we must first endure the limits of a system that we ourselves in the West have helped to create and maintain over several decades. Doing so without pushing those limits to their breaking point in response to the war in Ukraine will be the second task in the weeks, months, and perhaps years ahead.

But if nuclear proliferation is something that the majority of states find politically undesirable and nuclear disarmament is not feasible in realpolitik terms, how ought we to deal with the effects of an obviously precarious and unjust nuclear peace? The bitter answer is that we must first endure the limits of a system that we ourselves in the West have helped to create and maintain over several decades. Doing so without pushing those limits to their breaking point in response to the war in Ukraine will be the second task in the weeks, months, and perhaps years ahead. Where possible and agreeable, the West will continue to funnel weapons to help Ukrainians defend themselves. In doing so, NATO must keep two critical goals in mind: close alliance policy coordination, and walking the fine line between military support and the avoidance of unacceptable escalation risks.

Furthermore, the West would be well advised to continue to take note of and condemn Putin’s nuclear threats without mirroring them. Russian nefariousness should not tempt us to follow his lead. Finally, NATO will soon have to deal with the task of strengthening the assurance of its eastern allies. Which capabilities deter Russia the best in this regard will have to be determined by a detailed internal analysis – one that will take place under enormous time pressure due to the new geopolitical situation in Europe. The limited effectiveness of Russian nuclear threats against NATO as well as the abiding ability of each to deter the other from a direct conflict lends credence to the argument for focusing on the strengthening of conventional capabilities of NATO’s eastern flank. That more NATO nuclear weapons would change this state of affairs remains to be shown. Nevertheless, given its depleted conventional capabilities – a result of the war – Russia may come to rely even more heavily on dual-capable short- and medium-range systems in the future. This, in turn, would increase the pressure on European NATO allies. Germany is already experiencing a lively debate regarding the merits of scaling up missile defense for the country and its eastern neighbors.[11]

Even a precarious and unjust nuclear peace of this kind will require certain cooperative elements. If Russia is interested in a minimum of stability and risk reduction in the future, arms control will have to resume its original military task as a stabilizing element of mutual deterrence. In this sense, arms control must again be understood as “complementary to deterrence and defense”, as the new German Foreign Minister Annalena Baerbock recently put it.[12]


Concluding Remarks

For Ukraine – still at the mercy of the injustices of nuclear peace – these considerations are worth little for the time being. Until Vladimir Putin makes it clear that he is willing to accept an outcome that falls short of his maximum demands for the complete demilitarization of the country, a negotiated solution seems a distant prospect. The bloodshed will continue and might even soon extend to Moldova where Russia as well can leverage a secessionist ‘republic’ to stoke conflict.

Over the long term, however, we must consider how to organize peace, security, and justice in a more participatory and egalitarian way, in a world that still has more than 12,000 nuclear warheads. It has been 77 years since Hiroshima and Nagasaki. Today, a practical return to the goal of nuclear disarmament once again appears to be a generational task. We cannot let another 77 years pass before the world sees global peace, security, and justice.

[1] Speech by NATO Secretary General Jens Stoltenberg at the 16th Annual NATO Conference on Weapons of Mass Destruction, Arms Control, Disarmament and Non-Proliferation, 10 November 2020,

[2] Charter of Paris for a New Europe – OSCE (1990).

[3] Michael O’Hanlon, “The Cuban Missile Crisis provides a lesson to resolve the Ukraine crisis,” The Hill (10 February 2022),

[4] James Hohmann, “Why Biden’s response to Zelensky’s no-fly zone request was so wise,” Washington Post (16 March 2022),

[5] Adam Tooze, “Chartbook #92: "So like U.S." - Africa and the Russo-Ukrainian war,” Chartbook (5 March 2022),

[6] Oliver Meier, “Nuclear blackmail failing?” Twitter (1 March 2022),

[7] Maura Reynolds, “‘Yes, He Would’: Fiona Hill on Putin and Nukes,” Politico (28 February 2022),

[8] Anthony Zurcher, “Why Biden's off-script remarks about Putin are so dangerous,” BBC (27 March 2022),

[9] David E. Sanger, “Behind Austin’s Call for a ‘Weakened’ Russia, Hints of a Shift,” The New York Times (25 April 2022),

[10] Treaty on the prohibition of nuclear weapons - UNODA,

[11] Hans von der Burchard, “Germany debates buying Israeli missile defense system,” Politico (28 March 2022),

[12] “Security for the freedom of our lives,” Speech by Federal Foreign Minister Annalena Baerbock at the event to launch the development of a National Security Strategy, Auswaertiges Amt (18 March 2022),

Ulrich Kühn
Ulrich Kühn

Ulrich Kühn is Head of the Arms Control and Emerging Technology Department at the Institute for Peace Research and Security Policy at the University of Hamburg, Germany.

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