We Should Be Sober About the Risk of Nuclear Weapons in Ukraine

The risk of nuclear weapon use in Ukraine is low but rising. It’s deeply concerning. But we should also resist the kind of alarmism that is counterproductive to both principled internationalism and winning a world free of nuclear weapons.

Russian president Vladimir Putin speaks during the signing ceremony with separatist leaders on the annexation of four Ukrainian regions at the Grand Kremlin Palace, on September 30, 2022, in Moscow, Russia. (Getty Images)

What is the risk that Russia will fire a nuclear weapon in Ukraine? Commentators who support greater confrontation with Russia tend to describe the probability as low — so low, in fact, that we effectively shouldn’t worry about it at all. Others, including some on the Left, argue that the threat is terrifyingly high — high enough that it ought to take immediate precedence over Ukraine’s fight against an imperial occupier.

These perspectives are each half right — but also half wrong. There is a very real risk of nuclear weapons use in Ukraine, so much so that Daryl Kimball, executive director of the Arms Control Association, has described the situation as “one of, if not the most, severe episodes in which nuclear weapons might be used in decades.” At the same time, most experts still regard the likelihood as low. Isn’t that a contradiction?

Not really. The chances of nuclear use can be small but uncomfortably elevated when compared to the last few decades of relative calm. One can conclude that detonation is currently unlikely while still being very concerned about the high consequences of escalation. Similarly, one can be extremely unsettled by recent developments while recognizing that a nuclear crisis is still several major steps away. There’s no need to fall prey to the binary of denialism and alarmism.

In what follows, I sketch out a picture — the good, the bad, and the ugly — of nuclear risk at this moment. While it’s impossible to assign numerical probability to something so complex, the image that emerges is one of low but rising risk. Acknowledging the limits and uncertainties of this picture is important though — and analytical sobriety will be key for developing a substantive disarmament politics in the coming years.

The Good

The good news is that most experts agree the risk of nuclear use in Ukraine is still low. The taboo surrounding nuclear weapons in war has held for more than seventy-five years, despite several moments of serious crisis.

If he flouted the taboo, Vladimir Putin would face international outrage on a scale that dwarfs the sizable (though hardly universal) condemnation of his invasion of Ukraine. He would risk turning the neutral stance of Global South governments — which tend to support nuclear disarmament — into outright opposition to the war. He would also imperil the backing of China, which has maintained a policy against first use since its inaugural nuclear test in 1964. Internally, the appearance of nuclear weapons would make the war seem even less defensible and would likely swell the ranks of the Russian antiwar movement.

It is also highly unlikely that Putin would shoot off a nuclear weapon without any warning whatsoever. The United States clearly has intelligence sources in the Russian government and would probably learn about nuclear deployments before they began. (The US also has spy satellites capable of spotting telltale signs of preparations for nuclear use.) In the lead-up to the invasion, the Biden administration declassified intelligence to publicly expose Russia’s plans. If the United States determined Russia was seriously weighing the nuclear option, it would announce it to the world to pressure Putin to back down. Thankfully, there is reportedly no evidence that Russia is taking substantive steps toward the nuclear route.

Related, nuclear deployment would likely be preceded by a whole series of escalatory moves before it reached a point of crisis. While escalation is never good, each step serves as a signal to the relevant parties (and the global public) that risks are rising and, thus, off-ramps are necessary. Moving up the escalation ladder is not inevitable, in other words. Each rung presents an opportunity for cooler heads to prevail (although obviously much depends on our own capacity to demand de-escalation). It’s important to stay vigilant, but right now we shouldn’t push the panic button.

It’s also encouraging that the Biden administration has been fairly restrained given the tensions between (1) support for the Ukrainian cause and (2) the nuclear risks of confrontation with Russia. The administration resisted the push for a no-fly zone, declined to send troops to Ukraine, and has refused to meet Putin’s nuclear threats with its own — a wise decision that has apparently angered a few anonymous Dr Strangeloves in the military and intelligence apparatuses. To paraphrase FDR, Joe Biden should welcome their hatred. A nuclear-inflected conflict is no time for macho posturing.

The Bad

The bad news is that while the overall risk is low, it appears to be rising. Ukrainian victories have triggered increasingly desperate measures from Putin. Two of these measures, mobilization and annexation, have particularly worrisome implications for the nuclear threat.

The “partial mobilization” order is proof that the war is going poorly for Russia. On the one hand, this is clearly a good thing. Success on the battlefield is one of the few factors capable of pushing Russia to negotiate an end to the conflict. On the other hand, nuclear experts generally agree that Russian military losses will amplify the chances of Putin reaching for the nuclear option.

If the Russian position in Ukraine becomes dire, for example, Putin may come to view nuclear weapons as one of the only means to shift battlefield conditions. He might start by launching a so-called “demonstration shot” over a relatively depopulated area to display his willingness to go even further. Or, faced with a Ukrainian military striking fast and hard, he might fire off a tactical nuclear weapon to halt its advance. Either scenario would be a catastrophe.

The Russian annexation of four regions of Ukraine — none of which it fully controls — is a similar mark of desperation. Over the past week, Putin used illegal referenda to steal parts of Ukraine and formally add them to Russia. With the war failing, his actions may be intended to snatch a semblance of victory from the jaws of defeat, perhaps so he can, eventually, end the war on terms acceptable to domestic constituencies.

The heightened nuclear risk stems from the fact that, as part of “Russia,” the stolen territories could be defended with such weapons. Former Russian president Dmitry Medvedev, who has lately served as nuclear attack dog for the Putin government, made this point explicitly in September. His comments would be less worrisome had Putin himself not repeatedly stressed his willingness to defend Russia’s “territorial integrity” with “all weapons systems available to us” in the now-notorious speech announcing the mobilization.

To be clear, this is not official Russian policy, which still states the country will only turn to nuclear weapons if faced with an existential threat to the state (not its territory). That said, one can’t help but wonder if Putin is intentionally muddying the waters amid a flagging war effort.

Imagine: Ukrainian forces (justifiably) attempt to retake some or all the regions that Russia has annexed. Eventually, they gain the upper hand and push Russian troops into a seemingly hopeless position. Would Putin see this as a threat to Russia’s territorial integrity? He might — and disturbingly, he’s already constructed a pretext to use nuclear weapons. That doesn’t mean he will — but it’s not encouraging that last Friday, Putin said the United States created a “precedent” when it bombed Hiroshima and Nagasaki in 1945.

The Ugly

“Low but rising risk” seems empirically grounded to me. However, it’s important to recognize that there are a lot of things we don’t know about the chances of nuclear warfare in Ukraine. It’s all well and good to assess the known elements pushing the level of risk up or down, but there are also “known unknowns” that should keep us humble. I will mention two of them.

First, nuclear deterrence theory is partly speculative. The truth is we don’t have that many data points on what might drive a state or individual to utilize nuclear weapons in war. That doesn’t mean deterrence theory has zero validity — but a real-world conflict is never going to match the antiseptic world of academic thought experiments. Nor will a contemporary development ever be completely analogous to a historical event. We should be wary of trying to fit the square present into the round hole of the past. Only the Cuban Missile Crisis is the Cuban Missile Crisis.

Second, Putin himself is an X factor. After spending years in COVID isolation, receiving advice from a tiny group of people who are probably telling him what he wants to hear, the Putin of today may not be the Putin of five or ten years ago. Even the invasion itself could be interpreted as evidence of a shift. It was poorly planned, terribly executed, and — at least on the surface — strategically stupid. Putin’s invasion has resulted in Sweden and Finland joining NATO, whose expansion he has repeatedly decried. It has sent Russia’s economy into a recession and complicated relations with allies. It has created a domestic antiwar movement, which appears to be growing after the mobilization order. The decision to invade just doesn’t seem rational.

Does this mean Putin is simply mad? Absolutely not. Observers have crafted compelling arguments for the underlying logic of the immoral invasion, and it’s fair to assume Putin is still a more-or-less rational actor, much like Kim Jong-un or any other autocrat with nuclear weapons. However, one can be generally rational while still succumbing to (perhaps mounting) moments of recklessness. Putin’s recent actions should make us wonder how he would react when faced with a decision to stand down or escalate. A greater or lesser degree of irrationality could make all the difference in that kind of crisis.

The next several decades will be a time of growing nuclear threats. Forces are modernizing, arsenals are expanding, and great powers are competing. Ukraine will likely be only the first in a series of nuclear-inflected conflicts.

It is right to be concerned — even scared — about this brave new world. Certainly, fear is a more logical response than denying the risks exist. But building an alternative future requires that we steel ourselves for the years ahead. Burning ourselves out with alarmist terror isn’t a recipe for action — it’s a recipe for political paralysis.

It is better to assess nuclear risks with a clear eye. True objectivity is impossible, but a reasonably accurate image of current conditions is necessary to chart a path forward to both principled internationalism and a world free of nuclear weapons. Because after all, the point isn’t to interpret the world — the point is to change it.