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?

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.

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

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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.