Bombed homes in Borodyanka, Ukraine, and a damaged statue.
Russia exploited the “nuclear shadow” when it started its war against Ukraine. | Photo: Mikael Colville-Andersen via flickr | CC BY-NC 2.0

War against Ukraine: How to Make Deterrence and Arms Control Work

One year after the Russian invasion of Ukraine, experts from the United States, Ukraine, Germany, Turkey, and France discussed the consequences of the war for the nuclear world order in a workshop organized by PRIF’s French partner organization “Fondation pour la recherche stratégique” (FRS) and the “Odesa Center for Nonproliferation” (OdCNP). The focus was on the importance and limits of nuclear deterrence policy and arms control, disarmament, and nonproliferation.

Russia’s war, shielded by nuclear threats, raised two key questions. Does nuclear deterrence have the effect of promoting or limiting war? Do arms control, disarmament, and nonproliferation still matter, or have they become obsolete after Russia’s threats to break the nuclear taboo? Does its violation of the Budapest Memorandum (Mykhailo Soldatenko 2023; Mariana Budjeryn 2022) disqualify Moscow as an honest broker for arms control negotiations?

The following analysis does not represent the conclusions of the workshop. Instead, it independently explores the questions that were raised. Taking into account macro-developments in nuclear policy and arms control in the run-up to the Ukrainian war, and looking more closely at the interaction of deterrence and (arms control) diplomacy during the past year, it becomes clear that deterrence must be viewed in a differentiated manner and that arms control must be conceptualized comprehensively to ensure security and strategic balance and to avoid nuclear escalation both between nuclear-weapon states and at the expense of a non-nuclear-weapon state (Ukraine).

The deterrence and arms control prelude to the war against Ukraine

Overstretched extended deterrence and the question of credibility

Prior to the Russian invasion, the nuclear deterrence policies of the five nuclear-weapon states recognized by the Nuclear Non-Proliferation Treaty (NPT) encompassed a series of gradations of nuclear deployment scenarios of varying breadth. At the low end of this scale was a minimalist policy of first-strike renunciation while preserving a second-strike capability (which roughly corresponds to China’s nuclear doctrine). In the middle spectrum were nuclear doctrines that included attacks with other weapons of mass destruction (biological and chemical weapons) or vaguely defined threats to (national) state existence as justification for a nuclear counterstrike (with variances and depending on the period; the other four nuclear weapon states can be identified as belonging here). At the upper end was the model of extended deterrence, which included a so-called tactical use of nuclear weapons in the event of a conventional attack by a nuclear-armed adversary and, to bolster the credibility of this scenario, provided for the stationing of corresponding warheads and delivery systems on allied territory. This extended form of nuclear deterrence aimed at maintaining escalation dominance in the event of a direct military confrontation between the two blocs during the Cold War and was practiced by the United States and the Soviet Union within the framework of the so-called nuclear sharing of NATO and the Warsaw Pact, respectively.

Over the past twenty years, the center of gravity of the two great powers’ nuclear deterrence policies has always shifted within the middle and upper ranges of this scale, depending on the government and the state of relations. Most recently, however, a clear trend to expand nuclear deterrence and deployment scenarios prevailed during Donald Trump’s presidency. Russia’s annexation of Crimea in 2014, its hybrid war in Donbas and its practicing coercive threats towards the Baltic states and Poland contributed to a significant tightening of the U.S. Nuclear Posture Review (NPR) in 2018. This document describes Russia’s nuclear policy as relying on the mistaken assessment that “the threat of nuclear escalation or actual first use of nuclear weapons would serve to ‘de-escalate’ a conflict on terms favorable to Russia”. In turn, the U.S. NPR proclaimed the necessity to adapt the US nuclear forces to the tasks of waging regional wars not excluding first use of nuclear forces. In its 2020 nuclear doctrine, Russia moved the focus further to Western threats and regional war scenarios that could lead to nuclear warfare, reserving the right to use nuclear weapons to end conventional military conflicts. Today we know that for Putin, this implies also a “nuclear shadow” providing free hands in dealing with non-nuclear neighbors who do not belong to any alliance.

The expansion of nuclear deterrence and options for nuclear warfare (including threats of nuclear use) required corresponding material adjustments to maintain credibility. Therefore, both the U.S. and Russian sides launched massive modernization programs to provide appropriate delivery systems and warheads. Sub-strategic capabilities relevant for scenarios of nuclear regional war have increasingly come to the fore. This shows how closely the development of nuclear arsenals is linked to the existing formulation of nuclear deterrence. However, to ensure the credibility of the re-enforced extended deterrence policy and options of (sub-strategic) nuclear warfare, not only the corresponding nuclear capabilities had to be developed and provided. The arms control framework has also undergone a fundamental transformation that has extended the possibilities of nuclear warfare.

The erosion of arms control in Europe and growing hegemonic conflicts

During the same period, Europe underwent a phase of profound erosion of nuclear arms control. The termination in 2002 by the Bush administration of the ABM Treaty that limited missile defense and the build-up of the National missile defense (NMD) program had global implications on strategic balance. This triggered an arms race and a process of disintegration of arms control policy on the European continent that was subsequently driven by both Russia and the United States. This includes the halting of the update of the Treaty on Conventional Forces in Europe (CFE) due to the second Chechen war, the suspension of the treaty by the Putin administration in 2007, the termination of the INF Treaty for the elimination of intermediate-range missiles in 2020, pushed by President Trump, and the abrogation of the Open Skies Treaty for joint surveillance flights in 2021 (Kertsyova 2021; Woolf 2021). It is noteworthy that until then the dismantlement of the arms control architecture by the two mayor nuclear powers ran counter above all European security interests. Both the U.S.-Russia strategic dialogue and the arms control agreements on strategic forces, which primarily served the nuclear balance between the superpowers and their strategic security, remained less affected by the disintegration. In early 2021, the New START Treaty was extended for another five years, and the strategic stability dialogue continued by Putin and Biden in Geneva in June 2021 (Reif and Bugos 2021; Isaacs and Reif 2010; Williams 2023; Goettemoeller and Brown 2023).

The perishing of Cold War security mechanisms together with the degradation of arms control weakened the European continent’s security architecture amid a period of growing geopolitical tensions between the U.S./NATO and Russia, an increasingly nationalistic and imperialistic Russian foreign policy agenda, and virulent territorial conflicts on its borders, including that over Ukraine. While the United States continued to have, at least in theory, allied territory for tactical nuclear warfare, with its nuclear sharing and deployment of nuclear weapons in NATO member states, Russia lost this escalation option with the dissolution of the Warsaw Pact and the collapse of the Soviet Union. However, this has not prevented Russia from alluding to its “escalation for de-escalation” option in its nuclear rhetoric, trying to instrumentalize it in its war against Ukraine. In addition, on March 25, 2023, Putin declared his decision to deploy tactical nuclear weapons in Belarus. After unsuccessfully trying to stop increasing Western support for Ukraine by suspending Russia’s participation in the New Start treaty, the announcement of nuclear sharing with Belarus probably aims at the same concessions. Through this arrangement, Russia intends to achieve the ability to launch nuclear weapons missions from foreign territory. In early April, Russia claimed the handover of a nuclear missile complex to Belarus. According to Mink, training on sub-strategic nuclear weapons has already begun.

Examining the strategic background and evolution of nuclear deterrence and arms control throughout the past twenty years can neither justify nor explain Putin’s war of aggression and nuclear threats. Imperialist, chauvinist and, in part, religiously charged motives play a major role in Russian policy regarding Ukraine. However, the nuclear macro-developments of the past two decades need to be taken into account to properly assess the strategic dimension and escalation potential of this war. Preparations for deployment of Russian nuclear weapons on Belarusian territory through joint exercises and deployment of nuclear-weapon-capable delivery systems, the removal of nuclear-weapon-free status from the Belarusian Constitution, and the strengthening of the bilateral military cooperation are visible signs of this strategic dimension. It was also the strategic miscalculation of a perceived weakened West (illustrated by the U.S. withdrawal from Afghanistan, among others) that, from the Kremlin’s perspective, opened a window of opportunity and at least partly explains the timing of the Russian aggression. All of this shows that the strategic conflict with the West, even if it cannot be seen as the cause of Russia’s invasion of Ukraine, inevitably and increasingly shapes this war on Europe’s borders.

Targeted deterrence and diplomatic arms control in the Ukraine war

Russian deterrence erosion and destabilization

Facilitating its war of aggression on Ukraine with nuclear threats, the Kremlin has left the classical spectrum of nuclear deterrence described above. Russia exploited the “nuclear shadow” when it started its war against Ukraine in 2022, backing its power projection with active nuclear rhetoric aimed at keeping NATO out of the conflict (Facon 2022; Hautecouverture 2023). Russia’s breach of the Budapest Memorandum and its nuclear-shielded invasion of its nuclear-weapon-free neighbor have pushed nuclear deployment options to the extreme and thus perverted the concept of nuclear deterrence. Tragically, this has occurred at a time when the Biden administration was reviewing the aggressive U.S. nuclear posture under Trump and even considering a sole-purpose principle (Hadley 2022; Kristensen and Korda 2022) that would have come very close to a no-first-use doctrine.

Reiterating nuclear threats in ever-changing variations (alluding to a nuclear catastrophe in the Zaporizhzhya nuclear power plant, which its military forces have been occupying, the untruthful accusation against Ukraine of preparing attacks with “dirty bombs”(Al Jazeera 2022; Andés Gannon 2022), and relativizing the nuclear taboo (i.e. Putin reminding the U.S. had set a “precedent” with Hiroshima and Nagasaki and thus normalized the use of nuclear weapons), the Russian president has corroded the shared understanding of nuclear grammar built up over decades of strategic dialogue. Deprived of its predictability, however, nuclear deterrence loses its stabilizing effect, bringing the world on the verge of its most shaky variations, the stability-instability paradox.

On the one hand, the significance of Moscow’s nuclear threats and capabilities increases as Russia’s conventional weaknesses become more apparent. Missing Russian successes on the battlefield and Ukrainian terrain gains in the wake of the autumn 2022 counteroffensive appeared to increase the risk of nuclear escalation. On the other hand, constant exploitation of Russian nuclear threats gradually exhausts the credibility of Moscow’s nuclear deterrence. The Kremlin’s rampant use of nuclear threats has led to an attrition that has undermined its effectiveness. A culmination of this paradox was reached when, in late September 2022, amid a series of territorial losses, Moscow announced the annexation of the Ukrainian regions of Kherson, Zaporizhzhya, Luhansk, and Donetsk, which it only partially controlled and in which it subsequently suffered further territorial losses. This was coupled with Putin’s threat that the Russian Federation would defend the integrity of its territory by “all available means” to protect Russia and its people.

Moderation and rehabilitation of deterrence

How have the United States and NATO responded to Putin’s exhaustion of rhetoric nuclear arsenal and this paradox (virulence of Russia’s nuclear signaling and attrition of its nuclear deterrent)? From the beginning, since February 24, 2022, the U.S. and NATO have stressed the need to keep nuclear weapons out of this war and pursued a consistent policy of denuclearization of the conflict. Russian threats have not been reciprocated to avoid a spiral of escalation. In the run-up to the Nuclear Non-Proliferation Treaty Review Conference in August 2022 and at the conference itself, the three Western nuclear powers, the United States, France and Great Britain, contrasted the Russian threatening posture with their stance as “responsible nuclear weapon states” and strictly rejected “coercive deterrence” – regardless of the fact that deterrence policies of Western P5 members also contain coercive elements and do not rule out first strikes. De facto, they have pursued a no-first-strike policy in the Ukraine war, referring to the joint declaration of the five NPT nuclear-weapon states, or P5, in January 2022 that “a nuclear war cannot be won and must never be fought”. The expansion and attrition of Russia’s nuclear threats were met with a finely tuned deterrence policy of nuclear restraint.

The effectiveness of this policy became evident in the reaction to Putin’s declaration of annexation of the partially occupied territories. For the first time, the White House used an ambivalent formulation of deterrence in the Ukraine war that could be interpreted in both conventional and nuclear terms, with Biden warning of a “nuclear Armageddon” in the event of nuclear weapons use by Russia. The U.S. did not rule out the possibility of a nuclear response and at the same time made clear that it is ready and, also, capable of intervening directly in the war with a massive conventional strike. Corresponding proposals were discussed, primarily targeting Russian nuclear bases that could be considered for an attack on Ukraine. At the same time, the U.S. and Russia maintained private channel talks (Sonne and Hudson 2022; Kroenig 2022) and some time later the Russian authorities denied the intention to attack Ukraine with nuclear weapons. Against this confusing background, there is a risk that at some point the perception can prevail that no matter what happens, Russia will not be inclined to start a nuclear conflict with the West. In contrast, the threat of direct U.S. entry into war, backed by capabilities and concrete operational plans, was credible precisely because of the combination of ambivalent deterrence and strategic proportionality, and was thus able to help keep Moscow at bay in the months that followed.

Thinking arms control broadly during a crisis

Maintaining direct contact and dialogue between French President Macron, Chancellor Scholz and Putin was no less important for escalation management during the first phase of the war, as well as military contact points between the U.S. and Russian general staffs to avoid miscalculation and unintended escalation. Using channels of communication and risk-minimizing measures is part of the broad repertoire of arms control that takes on a prominent role, especially in times of crisis and in the absence of classical disarmament, arms limitation, and verification instruments. Another central element for containing the potential for nuclear escalation has been the expansion of de-escalating diplomacy beyond the bilateral level, through diplomatic demarches at the highest levels of government, particularly toward Russian sympathizers and friends, China and India.

In a meeting in November 2022, Chancellor Scholz and Chinese President Xi Jinping both stated that any threat or use of nuclear weapons in the Ukraine war would be unacceptable. A short time later, both China and India expressed clear criticism of Russia’s nuclear threats. At the G20 summit in Indonesia, a joint statement succeeded in significantly increasing pressure on Moscow to renounce nuclear threats. Similar formulations condemning nuclear threats and the use of nuclear weapons can also be found in the final declaration of the first meeting of states parties to the TPNW, which was adopted in June 2022 and backed by 66 non-nuclear-weapon states. Pressure from the international community, but especially from the ranks of the BRICS states and partners, did not leave Moscow unimpressed. For much of the fall and winter of 2022-2023, it had succeeded in substantially reducing the risk of nuclear escalation. Success or failure of arms control and diplomatic containment depend on whether dynamics of social pressure (group dynamics) can be manipulated in favor of risk aversion.


The hypertrophy of deterrence and the progressive erosion of arms control in Europe over the past twenty years are not sufficient explanations for Russia’s aggression against Ukraine and its obsession with having to defend itself against a perceived Western hegemony and threat. However, they do shape the strategic backdrop on which Russia’s war against Ukraine plays out, thus the potential for strategic escalation. The significance of the loss of strategic stability at the (geopolitical) macro level increases with the duration of the war. Obviously, the causal connection with the U.S. expansionist policy, with which Russia tries to justify the war, is constructed. However, the Russian narrative succeeds in convincing numerous actors, including China, India, South Africa, and Brazil, for historical reasons and convergence of strategic interests. Thus, overstretched deterrence and simultaneous erosion of arms control provide fertile ground while serving as a strategic justification foil for Russia’s war against Ukraine. The decoupling of deterrence and arms control have made the pre-war security environment fragile. Hypertrophic extended deterrence, rearmament and dismantling of arms control in Europe have created favorable conditions for the war of aggression.

This war shows further that it is not possible to say across the board whether nuclear deterrence has a stabilizing or de-escalating effect, whether it promotes or restrains war. We have to distinguish what kind of deterrence we are talking about in what (arms control) context. By extending its nuclear threats, Russia has repeatedly tried to manipulate the course of warfare in its favor and has so far failed to do so. Instead, clear signs of wear and tear on its nuclear deterrent are emerging, coupled with a loss of credibility. The U.S. and NATO in turn have succeeded in reducing the risk of escalation by consistently tabooing the use of nuclear weapons in the Ukraine war. Three factors were decisive in this: the Russian nuclear threats were not imitated, China and India as well as the G20 were diplomatically engaged into an anti-nuclear war alliance and this was combined with an ambivalent deterrence focusing on conventional counterstrike options.

Throughout the past year we have seen that nuclear arms control must be thought of more comprehensively than regulation and limitation of warheads and delivery systems. Especially in the context of a war with global escalation potential, creating the conditions of crisis stability and avoiding behaviors that increase the risk of nuclear escalation are crucial. Military points of contact, strategic risk reduction, risk mitigation, and preventing unintended escalation due to misinterpretation are central. At the same time, given the loss of trust in relations with Russia and its lack of reliability, other actors, especially China and India, but also other BRICS states, must be consistently engaged in de-escalation and arms control efforts. Countries outside the transatlantic area are becoming increasingly important for arms control arrangements in the future. Therefore, a reorientation of arms control policy towards multilateralization is necessary. The risk of actual use of nuclear weapons by Russia has varied significantly during the war. Risk management and substantial de-escalation have been successful through a precise formulation of U.S./NATO deterrence policy (nuclear restraint, credible conventional deterrence) in combination with bilateral contacts with Russia and diplomatic initiatives toward third parties sympathizing with Moscow. So far, nuclear (de)escalation management has worked out. But it has also shown the limits of deterrence and arms control policy: only together, and if credible, precise and complementary, can they have their stabilizing effect.

This article has previously been published as Note de la FRS n°11/2023 on the Fondation pour la recherche stratégique (FRS) website.

Sascha Hach

Sascha Hach

Sascha Hach ist wissenschaftlicher Mitarbeiter und 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.
Polina Sinovets

Polina Sinovets

Dr. Polina Sinovets ist Leiterin des Odessa-Zentrums für Nichtverbreitung und gleichzeitig außerordentliche Professorin an der Nationalen Universität Odessa I.I. Mechnikov. Zu ihren Forschungsinteressen gehören nukleare Abschreckung und Rüstungskontrolle, Kernwaffen sowie die russische Nuklearpolitik. // Dr. Polina Sinovets is the head of Odesa Center for Nonproliferation and also an Associate professor of the Odesa I.I. Mechnikov National University. Her research interests include nuclear deterrence and arms control, nuclear weapons, as well as Russian nuclear policy. | Twitter: @PSinovets
Polina Sinovets

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Sascha Hach

Sascha Hach ist wissenschaftlicher Mitarbeiter und 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.

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