Deterrence and Nuclear Weapons in Ukraine

nuclear weapons

By: Jakob Lindelöf

Picture credits: Johannes Daleng via Unsplash

The ongoing Russian invasion of Ukraine is now heading into almost one year of fighting. With the intended initial offensive only meant to last three days, early Russian successes in the field in the past few months have been replaced with successful Ukrainian counter-offensives along the frontlines around Kharkiv and Kherson. The military setbacks and mounting Russian casualties have led to the mobilisation of 300,000 conscripts and the formal annexation of four regions in Ukraine by Russia in a desperate act to solidify their claims through local referendums. With the self-recognition of these lands as Russian, combined with Russian President Putin’s threats of using  nuclear weapons to defend their territory, discussions over the use of nuclear weapons have begun to take hold. While Putin has denied that he will use these weapons in Ukraine, he also warned that his willingness to defend Russia’s territorial sovereignty was not a bluff. In March 2022, Russian nuclear forces were put on high alert, engaging in nuclear launch drills as part of these threats by sabre-rattling its nuclear capabilities to the world.

The recapturing of Kherson by Ukrainian forces has put Russia on the defensive by regrouping and digging in, most notably in Crimea. The Crimean Peninsula was annexed by Russia in 2014 and is also considered to be Russian territory by Putin, with his claim that the transfer of Crimea from the Russian Soviet Federative Socialist Republic to the Ukrainian Soviet Socialist Republic in 1954 was “a gross violation of legal norms at the end”. Ukrainian President Volodymyr Zelenskyy’s promise to retake Crimea, combined with the threat now posed to Russia after the fall of Kherson, means there may be attacks launched with the objective to free Crimea in the future. However, since Russia considers Crimea to be its home territory, any attack could trigger the threat of utilising the nuclear weapons that it has previously tried to coerce Ukraine and the West with.

Coercive diplomacy is when a state seeks to dictate the actions of another through the threat of the use of force or a limited military action. Regarding Ukraine, we can see the use of coercive diplomacy by Russia through the threat of nuclear weapons to defend itself, if forced to. This threat, therefore, like deterrence theory suggests, seeks to deter Ukrainian action by forcing it to refrain from attacking Russian territory. Russia also seeks to coerce and deter the West from escalating the war by sending arms to Ukraine by signalling its threats to the international community. These acts of coercion seem to have failed since many western countries are now sending tanks such as the much discussed Leopard 2.

For coercion and deterrence to work, it also means that threats need to be credible. For threats to be credible to the intended target and the international community, they must also be followed up on (otherwise one’s reputation is at risk). Therefore, the use of such coercive diplomacy in the form of threatening nuclear warfare cannot be ignored nor tolerated. It should be met with a credible commitment to respond to Russia with the threat of swift and decisive military and non-military action to deter the threat of and use of tactical or strategic nuclear weapons. However unlikely it is for Russia to deploy these kinds of weapons on the battlefield (and even less in population centres), a commitment should be made by the international community to deter Russia from engaging in nuclear coercion to impose its will on other states. There must also be a commitment made by members of the international community to actively punish transgressors of the international taboo of using nuclear weapons. If Russia’s claims are not met with strong and credible opposition, these threats risk becoming the new norm in diplomacy and potentially pave the way for the use of nuclear weapons in diplomacy and on the battlefield. 

Thus, the threshold and costs of using nuclear weapons on a non-nuclear power must be so high and come with retaliation from third parties that it becomes unthinkable to even consider using such weapons. This goes for any world power that has the capability of deploying nuclear weapons as a means of engaging in diplomacy or waging war. If deterrence fails and Russia’s nuclear threats are followed through in Ukraine, conventional military action must be taken, or the lack of serious commitment to opposing nuclear weapons would allow for this new reality of using nuclear weapons as more than bargaining tools – but as a viable military option.

The Scenarios of International Responses

If a nuclear strike instigated by Russia were to occur on Ukrainian soil, what should the response be from the international community? There are three options, each with its own set of actions, consequences, and implications for the future of international politics. 

The first would be no reaction or a limited response. This means that a nuclear strike would essentially be ignored by the greater international community or have limited repercussions, such as warnings or threats of further use on other powers but still no significant change in attitudes. A situation in which there is no response would signal to other nuclear powers that the international norms of non-use have been broken. We may then see nuclear threats as credible and potentially witness their use more commonly in international diplomacy. Non-nuclear powers (or those not under a nuclear umbrella) would be more susceptible to nuclear blackmail or risk having these weapons turned against them, as they could not retaliate with any comparable measures. 

The second possible response to a nuclear detonation in Ukraine could lead to a proportional nuclear retaliation by, for example, a NATO state. This is also extremely unlikely for two reasons. First, Ukraine is not under any nuclear umbrella (unlike NATO states which are covered under Article 5) and thus a non-Ukrainian nuclear intervention on Russian troops would be unlikely due to a lack of obligations towards Ukraine in terms of nuclear weapons. Second, a non-Ukrainian nuclear strike on Russia would require a Russian response of similar magnitude against the country retaliating on behalf of Ukraine. Following the doctrine of  Mutually Assured Destruction (MAD), this means that the use of nuclear weapons by one power against another requires that nuclear power to respond. An exchange of nuclear weapons in this manner could spiral into complete nuclear annihilation for all sides involved – including Ukraine. This would render the war meaningless, as all potential gains would be destroyed. Even if it  would not end in an all-out nuclear retaliation, there would be untold destruction. Alongside risks that come with nuclear retaliation against Russia, French President Emmanuel Macron announced that France would not respond with nuclear weapons if they are used, as it is not in their national interest.

If doing nothing paves the way for nuclear blackmail and a nuclear response could lead to paramount destruction, how should states adequately respond by punishing the aggressor, while not incurring destruction?  The best-case scenario would be the third path, which includes pre-attack deterrence or prevention. This form of deterrence or coercion by a third party (the West, for example) means creating a credible commitment that the international community will act against any strike as deterrence and the eventual use of conventional arms as punishment. These actions would have significant consequences for Russia, which would have to alter its cost-benefit calculations for launching a nuclear strike. If a nuclear strike against Ukraine were to take place, the international community would be prompted to act swiftly in retaliation in both military and non-military capacities. These must be decisive enough to either stop any continuation of a one-sided nuclear war or destroy Russia’s capacity to wage war. This level of response would, therefore, signal to the nuclear aggressor the unacceptability of such actions. If no action is taken after third-party deterrence has been signalled but failed in its attempt to deter nuclear action, this would also lead to loss of credibility.

In this scenario, for example, military actions against Russian forces could be a set of conventional non-nuclear strikes and attacks to stop Russian capabilities from waging an aggressive war in Ukraine whilst also avoiding a nuclear exchange between nuclear powers. The question, however, remains of who will attack and what will be attacked. How far will these strikes go? The use of a conventional military response also comes with considerable risks. Will Russia, which has already used nuclear weapons, respond similarly against intervening countries despite them not using nuclear arms? Conventional strikes made against military infrastructure could, for example, inadvertently take out nuclear capabilities and thus be perceived as a preamble to a nuclear attack by attempting to limit Russia’s ability to counter.

Alongside military action, international condemnation of the use of nuclear weapons by third parties not directly involved with the war would be key in assuring the success of the deterrence strategy, especially from larger states such as China, India, and Brazil. As military action would likely come from the West, the condemnation of using nuclear weapons by major non-Western countries would be vital in upholding normative values. Without such support, the escalation of the war would only devolve into ‘might makes right’ rather than the upholding of international principles. Non-military action also includes harsh economic and financial sanctions from the international community to put pressure on Russia and potentially cripple their ability to continue waging war. 

International action also includes the ostracisation of Russia from various international institutions and events to enforce normative pressure.  

Russia’s justification for its threats

Russia’s justification for the potential use of nuclear weapons against Ukraine bases itself on the United States’ use of atomic weapons 77 years ago against Japan during World War II. Since then, nuclear weapons have not been actively deployed during wartime. Putin, however, argues that the US set the precedent for the use of nuclear weapons and that, therefore, Russia would be justified in using the same tactics. However, the international community has come together since 1945 to limit the spread and use of nuclear weapons through the signing of multiple treaties such as the Treaty on the Non-Proliferation of Nuclear Weapons, Comprehensive Nuclear-Test-Ban-Treaty, the Strategic Arms Limitation Treaty (SALT I & SALT II), the Strategic Arms Reduction Treaty (START), and New START. Despite the various incidents that have occurred with nuclear weapons in the last 77 years, the fact that they have not been used and that there has been an effort to reduce nuclear stockpiles has set a precedent for non-use.


As long as nuclear weapons exist, we must accept that there is a risk that they can be used. In such a world, states must act against their use as diplomatic tools to coerce others. The normalisation of nuclear weapons and the breaking of the nuclear taboo would be disastrous for international politics, as it risks destruction unseen since Hiroshima and Nagasaki. China’s President Xi Jinping has already warned Russia not to use nuclear weapons in Ukraine and called for the international community to oppose their use. The United Nations Secretary-General António Guterres has also condemned the threats of nuclear weapons, along with several leaders at the G-20 summit in Indonesia. However, while the international community has condemned these actions, they currently carry little promise of retaliation. As a result, the open threats made by Vladimir Putin to deploy nuclear weapons means the international community must have a plan on how to respond in case such an event was to occur. The threat of nuclear weapons should be met with a response to change Russia’s cost-benefit calculations. Not only should Russia be deterred from deploying such weapons in Ukraine, but there should also be active efforts to prevent this rhetoric from becoming used in the future. Any nuclear action must come with a heavy cost in terms of economic sanctions, international condemnation, and potential military action to prevent this kind of behaviour from occurring and becoming the new norm in the sphere of international politics. There is no doubt that a situation that necessitates a military response would bring further destruction through conventional means, but it prevents destruction through nuclear means. Another question that arises is: what will Ukraine itself do in the event of nuclear weapons being deployed in their country?

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