When the unthinkable becomes thinkable, it’s a crisis. And when the unthinkable actually happens, it is a catastrophe. Much effort will be spent on rebuilding what has been destroyed in Ukraine, and not nearly enough effort will be spent on rethinking our assumptions. Because we were wrong in our assessments of what is possible, we must change not only how we do business, but how we think about risks and rewards.

Attacks on and hostage-taking at nuclear power plants, the bombings of refugee convoys and maternity hospitals—these were previously unthinkable actions. They are now a reality. Russia’s annexation of Crimea in 2014 was meager preparation for the full-blown assault that has made a mockery of the political order that was established in the wake of World War II. Western observers are shocked, and for good reason. Russian forces and, especially, Russian President Vladimir Putin are willfully flouting standard conventions of acceptable behavior.

Conventional war in Europe is shocking enough, but Putin has also raised the specter of weapons of mass destruction (WMD). Did Putin put nuclear forces on alert, or was this a feint? Does it matter? Other WMD lies propagated by Russia are easier to disprove: that Ukraine intends to create nuclear weapons; that it has mined nuclear fuel with the intention of creating dirty bombs to use against or blame on the Russians; and that the US and Ukraine were fabricating biological warfare agents in a variety of laboratories. These lies are not meant to scare the opponent into inaction, as nuclear threats are. Instead, they could be laying the groundwork for a nightmare scenario in which Russia uses weapons of mass destruction against Ukrainians, but blames the attack on Ukraine. A kinder explanation suggests that Russia seeks a face-saving rationale for having gone into Ukraine in the first place, one that echoes the US invasion of Iraq in 2003.

Disinformation in wartime is a time-honored tradition. It is a tool of both the weak and the powerful; it is cheap, quick, and easier than spilling blood. With the advent of the internet, the spread of disinformation is global. And while it may be hard to precisely target the consumers of disinformation (although the vast amount of data out there about individuals has improved precision), it is harder to control once employed. A corrupted information ecosphere, could, in fact, outlast the war, with many people believing nonsense such as the laughable Russian claim that Ukraine is governed by Nazis.

Disinformation can be particularly dangerous when it comes to avoiding nuclear war. Credibility is essential to nuclear deterrence, which rests on perceptions of the threat. Nuclear weapons have always relied on secrecy, and in one sense, bluffing. But secrecy is one step removed from disinformation; disinformation is essentially deception. Uncertainty plays a role in deterrence, but an opponent who has learned to mistrust everything may become overly confident. Perhaps this partly explains Putin’s miscalculation in invading Ukraine.

The nuclear unthinking. Einstein correctly noted in 1945 that “the unleashed power of the atom has changed everything save our modes of thinking and we thus drift toward unparalleled catastrophe.” Perhaps he would not be surprised that more than 75 years later, the world still teeters on the brink of unparalleled catastrophe.

On February 24^th, Putin declared in a speech that “[n]o matter who tries to stand in our way or all the more so create threats for our country and our people, they must know that Russia will respond immediately, and the consequences will be such as you have never seen in your entire history (emphasis added). No matter how the events unfold, we are ready. All the necessary decisions in this regard have been taken. I hope that my words will be heard.”

Such language allows a wide choice of disastrous responses by Russia to outside interference, including the use of nuclear weapons. So far, Ukraine’s allies have not been deterred from sending aid. If they had been, it would have been easy to conclude that nuclear weapons will always favor the aggressor. There may additional nuclear threats issued by Putin in the coming weeks.

The phrase “a nuclear war cannot be won and must never be fought,” coined during the darkest days of the Cold War, recognized that a massive exchange of nuclear weapons would produce no victor, or at least not a victory that would be celebrated. With the fall of the Soviet Union, fears of such a massive exchange became a hazy memory. In late 2021, however, China, France and the UK joined the United States and Russia in repeating that declaration, which rejects nuclear war.

In the midst of the devastating war in Ukraine, the declaration now seems at the same time quite necessary and quite hollow. The prospect of a massive nuclear exchange has once again become thinkable as a spin-off from the conflict in Ukraine. Several scenarios are not impossible or crazy—accidental or inadvertent use leads to escalation, or a conventional rout backs Putin into a corner of desperation in which he plays the only card that still makes Russia a superpower, its nuclear weapons. Analysts would normally take comfort in knowing that authority to launch nuclear weapons resides in the head-of-state, rather than in battlefield commanders, but in the case of Russia, this concentration of authority may induce alarm. Putin seems determined to carry out his military objectives, at a higher cost to his military, his country, and himself than anyone could have guessed.

It took 40 years for the leaders of the Soviet Union and the United States to realize that a nuclear war cannot be won, and a few decades for the leader of Russia to forget that lesson. When the existential and dialectical competition between communism and capitalism evaporated, many assumed the threat of a massive exchange of nuclear weapons also evaporated. But leaving the weapons in place – reduced though still numbering in the thousands – did not actually reduce the threat. Reality bumps up against perceptions.

However the invasion ends, the way the world thinks about nuclear weapons will have to change.

If the war that Russia continues to wage on Ukraine ends without a nuclear weapon being fired, it will be a victory not for deterrence, but for disarmament. Such an outcome will demonstrate that nuclear weapons remain, 75 years after their invention, unusable, irrelevant, and a terrible waste of money, effort, and lives. Implementing nuclear disarmament will require changing our mode of thinking; we will have to stop believing, for instance, that nuclear weapons have spared us from conventional wars, that nuclear weapons are prestigious, and that nuclear weapons bring security, as opposed to existential dread. It will mean changes to how we order the world—from international organizations (a new UN Security Council with different members may well be considered), to military alliances and treaties that no longer enshrine nuclear weapons ownership.

A “small” nuclear exchange over Ukraine could lead to the same conclusion—that nuclear weapons are irrelevant to achieving military and political objectives. Use of a single weapon by Putin to coerce Ukraine into submission will never cement Russia’s empire, but instead result in global isolation for Russia. Use of a weapon against NATO also will not achieve Russia’s objectives, because NATO will not be deterred from retaliation—likely with conventional weapons—and the full weight of NATO against Russia (and perhaps Belarus) would be overwhelming.

Finally, if escalation led to a massive exchange of nuclear weapons, the world would experience a catastrophe of immeasurable proportions. This would prompt, undoubtedly, a change in our modes of thinking about nuclear weapons. It would happen automatically, as the living envied the dead.

Sharon Squassoni