The truth about nuclear deterrence

Why Russia could use nuclear weapons, and how to respond

Putin has made thinly veiled threats about using nuclear weapons against those who interfere with Russia’s invasion of Ukraine. The logic of nuclear deterrence suggests that it’s never in the interest of a nuclear power to engage in war with another country possessing nuclear weapons, as that would lead to mutually assured destruction. But preventing nuclear war is not the sole goal of any nuclear power. Putin might well believe that a world without Russia in its rightful position of power is not worth existing. We can’t be sure of what Putin is thinking, or whether his decision making is compromised – all we can do is prepare for the possibility of Russia’s use of nuclear weapons, writes Herbert Lin.


As the Russian invasion of Ukraine unfolds, Vladimir Putin has raised the spectre of using nuclear weapons to achieve his goals several times. On February 24, 2022—the day Russia launched its assault on Ukraine—Putin threatened any interfering parties with consequences “such as you have never seen in your entire history,” a statement widely interpreted as a nuclear threat. On February 27, Putin announced “a special combat duty regime in the Russian army’s deterrence [nuclear] forces." On March 1, Russia’s Northern Fleet said that several of its nuclear submarines were involved in exercises designed to “train maneuvering in stormy conditions,” while the Russian defense ministry said that mobile nuclear missile launchers had dispersed in Siberia to practice secret deployments.

Much of the commentary regarding Putin’s possible nuclear use suggests that such use would only occur in the event of a real or even misperceived NATO or U.S. military intervention to support Ukraine. Others have suggested that Russian nuclear use could occur even absent such intervention out of Putin’s frustration that the invasion has not proceeded more smoothly or as he expected.

Would Putin really use nuclear weapons to achieve his goals?

The Logic of Nuclear Deterrence

Strategic thought about nuclear weapons is based on a number of undeniable realities. Nuclear weapons are vastly more powerful than conventional weapons, and both Russia and the United States each have several thousand of them. The explosion of even one nuclear weapon could cause hundreds of thousands of deaths and trillions of dollars of damage. Neither Russia nor the United States have defenses that could completely protect their territories against nuclear weapons.  No one knows a way that either nation could “turn off” the other side’s nuclear weapons, fantastical thinking about cyber warfare notwithstanding.


Many have argued that “mutual assured destruction” and mutual vulnerability to nuclear weapons has kept the nuclear peace since Hiroshima.


Given these realities, the only way to prevent nuclear catastrophe is to persuade adversarial leaders who control each nation’s nuclear weapons to refrain from using them. The classic way for A to deter adversary B is to persuade B that the costs B would suffer, should B use nuclear weapons against A, far outweigh any conceivable benefits that B would gain from such use. Knowing this, the hope is that B will decide that using nuclear weapons isn’t worth it.

Many have argued that “mutual assured destruction” and mutual vulnerability to nuclear weapons—described in oversimplified terms above—has kept the nuclear peace since Hiroshima. At bottom, it presumes that all nuclear powers recognize their ultimate self-interest in avoiding nuclear war, since nuclear war would lead to devastation for both sides.

But this neat picture becomes very messy very quickly when one realizes that nations have other goals in addition to that of avoiding nuclear war. If its only goal were to avoid nuclear war, the United States could just dismantle all of its nuclear weapons unilaterally. In reality, both the United States and Russia have multiple goals. In the Russia-Ukraine conflict, the United States wants to avoid nuclear war, but also to thwart Russia’s attempt of reintegrating Ukraine into the Russian orbit, as well as dissuading Russia from invading other countries in the region. To achieve these other goals, the U.S. must be willing to take on some risk of not achieving the first.


Once Russia uses nuclear weapons, there is no easy way out.


How to respond in the case of Russian nuclear use?

To make this more concrete, one might imagine that Russia used a few dozen of its many nuclear weapons against the NATO nations supplying Ukraine with weapons and other materiel support. The terms of the NATO alliance say that the United States would respond to such an attack—but how?  What would be the appropriate U.S. response? Should it respond with nuclear weapons itself?  If so, against what targets? And if those targets were Russian, what prevents Russia from further escalation with more nuclear weapons?

Although it is stated U.S. policy in the 2018 U.S. Nuclear Posture Review that the United States “will strive to end any conflict at the lowest level of damage possible and on the best achievable terms for the United States, allies, and partners,” the escalatory spiral ends only when both sides use all eight thousand nuclear weapons at their disposal or when one side chooses to stop. But the side that chooses to stop first is quite arguably the loser. If it is the United States, it would have to concede to Putin’s goals, which by that point might include a lot more than control of Ukraine. If it is Russia that backs down, Putin would have to concede defeat in a war he started, a humiliation few believe he is willing to entertain. Neither outcome is palatable for either party. But, of course, if neither side stops, the resulting game of continuing nuclear tit-for-tat results in annihilation for everyone.

Once Russia uses nuclear weapons, there is no easy way out. The problem is that Putin may believe that, following the first Russian use of nuclear weapons, the United States and NATO would concede rather than go down this escalatory path to total annihilation. Any Russian nuclear use at all, even if non-lethal, would be reported around the world and could be expected (not unreasonably) to generate huge amounts of public concern and anxiety. Under these circumstances, large parts of Western citizenry would most likely begin to question whether solidarity with and support for Ukraine are worth further risks of nuclear war.


Discussions of nuclear strategy have rested on the assumption that we understand how adversary decision makers think.


This conundrum has bedevilled nuclear strategists for over half a century now.  Some strategists have advanced the idea that targeting the other side’s nuclear forces could reduce damage to one’s own side, essentially arguing that fewer nuclear weapons landing on one’s own nation is a better outcome than more nuclear weapons landing on it. Threatening the other side’s weapons, they further argue, will persuade the adversary to back down in a confrontation. However, Russia’s ability to devastate the United States will remain intact regardless of how the United States targets Russian nuclear forces, and in the end the conundrum cannot be resolved.

Even worse, discussions of nuclear strategy have rested on the assumption that we understand how adversary decision makers think. For example, many presume that adversary decision makers will act in accordance with their best interests, estimating the likely costs and benefits of all possible courses of action, and selecting the ones that offer the best outcomes—national survival being an essential part of any optimal outcome.

But, in fact, no one knows how Putin is thinking today or what he will do tomorrow. A substantial body of research in psychology—including three Nobel Prizes related to behavioral economics—has shown that in much of human decision making, and especially when humans are under stress, people often take mental shortcuts, consider only a limited number of alternatives, act impulsively, and take enormous risks to avoid losing. With the realization that Putin has been nursing a number of grievances against the West for at least two decades and the accounts indicating he is getting advice only from a small number of people selected in large part for their propensity to agree with him, it is fair to wonder if Putin’s decision making has been compromised, and how such compromise may have driven his decision to invade Ukraine.


Convinced of Russia’s greatness, Putin may well imagine that a world without Russia in its rightful place is worse than a smoking, radiating sphere that was once the planet Earth.


Preparing for the worst

Looking forward, Putin’s nuclear threats may be a bluff—an example of the deliberate “madman” theory of nuclear strategy first advanced by U.S. President Richard Nixon. Under this theory, a nation confronting a seemingly crazy and unpredictable adversary leader is fearful that even a small action might push that leader over the nuclear edge, and thus refrains from taking even small actions. Or Putin may be entirely willing to “go nuclear.” Convinced of Russia’s greatness and rightful place in the world order, Putin may well imagine that a world without Russia in its rightful place is worse than a smoking, radiating sphere that was once the planet Earth.  If he does, future historians—if any are alive—will wonder about why the West did not take his threats more seriously. But with no reliable crystal balls available to us today, we cannot tell in the present whether he is bluffing strategically or willing to pull down the whole world if he cannot attain his goals.  Indeed, he may well not know himself what he will do if events in Ukraine (and, God forbid, other parts of Europe) spin out of control and diverge from his preferred outcomes.

Given the above, how should the U.S. and its allies move forward today? Three steps may be useful.

First, the cognizant nuclear authorities in the United States and other Western nuclear powers should be planning for responses to a full range of contingencies involving Russian first use of nuclear weapons. These are not limited only to use in Ukraine, but also include use against a NATO nation that appears to be overly involved in assisting Ukraine and use in a non-lethal demonstration strike over open ocean. An important aspect of such planning goes beyond operational matters to consider how best to resist what will be intense political pressures to take actions that provoke further escalation.

Second, maximizing the operational transparency of U.S. and Allied forces would be wise. For example, any change in nuclear readiness of U.S. nuclear forces should be accompanied by an appropriate messaging strategy, likely involving public and private messaging. The content of such messaging should be at least provisionally planned so that the messaging strategy can be implemented quickly if necessary, and multiple lines of communication (e.g., military-to-military active-duty and retired, informal non-government “Track II” communicators) should be built and reinforced before nuclear use.

Third, the prospect of deep international isolation and condemnation could serve as a deterrent to first nuclear use for a Russian leader that craves respect above all else. Thus, it would make sense to start to assemble a global consensus on this point.

During the Cuban Missile Crisis, President Kennedy estimated the odds of war between the United States and the Soviet Union at somewhere between 1/3 and 1/2. From a risk perspective, the Russian invasion of Ukraine has not yet reached these proportions—a wild guess might rate the severity of the present situation as about 10 or 20 percent of a Cuban Missile Crisis. Still, measuring the current situation against the event that was the closest that the world has ever come to global nuclear war is sobering and a stark reminder of the stakes involved. We can only hope that wise heads prevail in not going down the nuclear path in the first place.


*Herbert Lin is solely responsible for the content of this article.

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