Will the Ukraine war fuel nuclear proliferation?

CAMBRIDGE  —  When the Soviet Union collapsed in 1991, Ukraine inherited part of its nuclear arsenal. But in the 1994 Budapest Memorandum, Ukraine agreed to return these weapons to Russia in exchange for “assurances” from Russia, the United Kingdom, and the United States that its sovereignty and borders would be respected. Russia brazenly violated this promise when it annexed Crimea in 2014, and tore up the Memorandum with its full-scale invasion of Ukraine on February 24. Many observers have concluded that Ukraine made a fateful mistake by agreeing to surrender its nuclear arsenal (once the world’s third largest). Are they right?

In the early 1960s, US President John F. Kennedy predicted that at least 25 states would have nuclear weapons by the following decade. But in 1968, United Nations member states agreed to a non-proliferation treaty that restricted nuclear weapons to the five states that already had them (the US, the Soviet Union, Britain, France, and China). Today, just nine states have them, the five named in treaty signatories plus Israel, India, Pakistan and North Korea, but there are more “threshold states”, countries with the technological ability to build nuclear weapons quickly, considering the option.

Some analysts suggest that proliferation might be a good thing, because a world of nuclear-armed porcupines would be more stable than a world of nuclear wolves and unarmed rabbits. In their view, Russia would not have dared to invade a nuclear-armed Ukraine. Moreover, they question why some states should have a right to nuclear weapons while others do not.

Others advocate the abolition of all nuclear weapons, a goal enshrined in the 2017 UN Treaty on the Prohibition of Nuclear Weapons, which entered into force in 2021. It currently has 86 signatories and 66 parties, though none of the nine states with nuclear weapons have signed up.

Skeptics of this approach argue that while nuclear abolition may be a worthy long-term aspiration, efforts to get there too quickly could increase instability and the likelihood of conflict. The real ethical challenge, they maintain, is not nuclear weapons’ existence but the probability of their use. It might be better if humanity had not learned to harness the power of a split atom in the 1930s; but that knowledge cannot be abolished, so it is better to focus on reducing the risks of its use in warfare.

Suppose that you live in a neighborhood that suffers continuous devastating break-ins, burglaries, and assaults. One day, some of your neighbours decide to equip their houses with massive explosive devices and trip wires, and post warning signs to deter intruders. The problem is that if these devices are used, your house will be damaged, too. Yet there are also considerable dangers in trying to dismantle the system in the short run.

What would you do? You might ask your neighbours to use the system only to defend against intruders and not to threaten others. You could encourage them to install devices to reduce the risk of accidents and demand compensation for the risk they impose on you by including your house under their warning signs. And you might persuade them to take steps to dismantle the system sometime in the future, when relatively safe means can be found.

By rough analogy, these are the types of conditions enshrined in the 1968 Treaty on the Non-Proliferation of Nuclear Weapons (NPT), and that is why the Russian invasion of Ukraine is so damaging. Russia has not only violated its explicit security guarantee under the Budapest Memorandum; it has also hinted at nuclear escalation to deter others from coming to Ukraine’s aid. It is thus weakening the taboo against treating nuclear weapons as normal war-fighting weapons, a convention that the Nobel Laureate economist Thomas Schelling called the most important global norm since 1945.

But it would be a mistake to exaggerate the harm that the invasion of Ukraine has done to the non-proliferation regime. For one thing, those who think the invasion will teach other states that they would be more secure if they had nuclear weapons are oversimplifying history. One cannot assume that nothing would have happened if Ukraine had kept its Soviet-era nuclear weapons.

After all, such weapons do not come ready to use “off the shelf”. The fissile material in the long-range Soviet missiles stationed in Ukraine would have had to be removed, reshaped, and repurposed. Not only would that have taken time and expertise, but it might have accelerated Russia’s intervention. When states approach the nuclear threshold, they enter a “valley of vulnerability” that may reduce their security and increase general instability. Even when stable deterrence is imaginable in a region, it may be highly risky to try to get from here to there.

Some theorists argue that just as nuclear weapons encouraged prudence among great powers, by giving them a “crystal ball” with which to foresee the devastation that would follow from nuclear war, the spread of nuclear weapons would similarly produce stability among smaller regional rivals. Nuclear porcupines would act like rabbits, not wolves.

But not all regions are equal in terms of escalation risk, and it cannot be assumed that all leaders would have the wisdom to use their crystal balls. Regions differ in terms of the number of civil wars and overthrown governments, civilian control of the military, the security of communications and weapons-control protocols. If new proliferators have a higher risk of using nuclear weapons, even if inadvertently, they and their neighbors will become even more insecure in the “valley of vulnerability”.

Ultimately, when nuclear weapons proliferate, the chances of inadvertent or accidental use tend to increase, managing potential nuclear crises becomes more complicated and establishing controls that may someday help to reduce the role of nuclear weapons in world politics becomes more difficult. In short, the greater the spread of supposedly defensive weapons, the higher the risks of blowing up the whole neighbourhood. The real lesson from Russia’s war in Ukraine is that we must reinforce the existing NPT and refrain from actions that erode it.

Joseph S. Nye, Jr., a professor at Harvard University and a former US assistant secretary of defence, is the author, most recently, of “Do Morals Matter? Presidents and Foreign Policy from FDR to Trump” (Oxford University Press, 2020). Copyright: Project Syndicate, 2022.

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