What would it take for Putin to use nuclear weapons in Ukraine?

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Would Vladimir Putin let Russia lose in Ukraine before using his nuclear weapons?

Can a nuclear power be defeated in a war by a non-nuclear power? At first glance, the answer seems quite obviously, yes. The United States military was defeated in Vietnam. Both the U.S. and the Soviet Union retreated ignominiously from Afghanistan. But these were lopsided counterinsurgencies — “small wars in faraway places,” to use one historian’s phrase, in which the more powerful nation eventually lost the political will, rather than the military capability, to continue fighting.

The war in Ukraine is something different — and without precedent: a conflict in which a nuclear power is in a full-fledged conventional war with a non-nuclear power. And Russian President Vladimir Putin and his government have often framed the conflict as a life-or-death struggle against Western military, economic and cultural encroachment.

In his address to the nation Tuesday, Putin did so again, and added a not-so-veiled reminder about his nuclear option. Addressing the countries backing Ukraine, Putin said, “I want to remind you that our country also has various means of destruction, and some components are more modern than those of the NATO countries.” He added that he was “not bluffing.”

Misleading as Putin’s framing of the conflict may be, his threats must be taken seriously — primarily because the outcome of the war may be an existential question for Putin’s own regime.

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Despite the success of Ukraine’s recent offensive around Kharkiv, there may still be much more fighting to come in this war, and a Russian defeat is still far from inevitable. But in stark contrast to many predictions at the outset of the conflict, it also does not look inconceivable.

This raises the uncomfortable question of whether Putin would really allow his military to be defeated on the battlefield without using every weapon at his disposal — including the world’s largest nuclear arsenal.

Recent comments from Russian officials have not been reassuring on this front. Former Russian president Dmitry Medvedev, now chair of Putin’s security council, warned earlier this month that Western powers were trying to break Russia apart, saying, “a forceful disintegration of a nuclear power is always a chess game with Death, in which it’s known precisely when the check and mate comes: doomsday for mankind.” He added that “the best guarantee of safeguarding the Great Russia” is its nuclear arsenal. This was somewhat mild compared with the sort of rhetoric about the nuclear option that is now regularly spouted by pundits on Russia’s state television networks.

The Russian government raised the stakes in a different way this week by announcing referendums that would formally annex a large swathe of Ukrainian territory, including the provinces of Donetsk, Luhansk, Kherson and Zaporizhzhia, all of which are currently active battlefields. In theory, Russia could then consider attacks on those regions to be attacks on Russian territory. As Medvedev put it after the annexation plans were announced, “Encroachment onto Russian territory is a crime which allows you to use all the forces of self-defense.”

The threat of nuclear weapons use has hung over this war since it began in February. But for all the saber-rattling and dire warnings, there have been no indications that Russia is actually preparing to cross the nuclear Rubicon. But if defeat really did look imminent, could that change? The talk of “all the forces of self-defense,” taken together with Putin’s warning of “various means of destruction,” suggest the possibility of a Russian nuclear response looms larger than it has since the war began.

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In a “60 Minutes” interview last weekend, President Joe Biden was asked what his message to Putin would be about this nightmare scenario “Don’t. Don’t. Don’t,” the president replied. “It would change the face of war unlike anything since World War II.” He added, without elaborating, that the U.S. response to nuclear weapons use in Ukraine would be “consequential.”

Nuclear weapons: What are they good for?

Given that no country has used a nuclear weapon since 1945, one might reasonably ask whether there’s any point in having them. For some countries, nukes are a means of deterring attack or invasion. See, for instance, the legislation passed by North Korea’s rubber-stamp parliament earlier this month, which declared that it would launch its nuclear weapons if the existence of the country or its government were under threat. Similarly, Russia’s official nuclear doctrine states that a first use of nuclear weapons is permissible only when “the very existence of the state is under threat.”

The problem, in a dictatorship like Russia’s, is that one man gets to decide what constitutes such a threat.

The threat of nuclear weapons can also be used by countries to back up conventional military force. When Putin first sent troops into Ukraine on Feb. 24, he threatened any country that might “hinder us, and … create threats for our country” with “such consequences that you have never experienced in your history.” In other words, back off or risk nuclear war.

This threat has worked to a degree. The U.S. and NATO have refused Ukraine’s pleas since the start of the war to establish a “no-fly zone” over Ukraine, since doing so would risk direct combat between Western and Russian aircraft. And because of fears of starting “World War III,” the Biden administration is still holding back on providing some weapons systems to Ukraine, such as long-range ATACMS missiles. The fear is that the use of NATO weaponry to attack Russian territory might lead to an escalation by Putin that could reach to the nuclear option. (The U.S. prohibition, notably, does not include Russian-annexed Crimea and presumably won’t include Russia’s newly annexed territories either.)

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But the nuclear threats are getting less effective over time. At the outset of the war, the White House wouldn’t even acknowledge sending Ukraine drones — much less precision-guided rockets, high-altitude air defense systems or the actionable targeting intelligence Ukraine has used to hit artillery depots and senior Russian commanders, fearing that disclosure would invite a Russian response. Clearly the line of what’s considered dangerously escalatory has shifted. When the Russian government now says that long-range missiles would cross a “red line” that would make Western countries a party to the war, it’s worth keeping in mind that Putin once said the same thing about any lethal aid to Ukraine.

Pavel Podvig, an expert on Russia’s nuclear forces at the U.N. Institute for Disarmament Research, told Grid that this “salami slicing” of what is actually considered escalatory is evidence that “Russia’s nuclear weapons don’t do it much good.”

The “cornered rat” theory

In a recent piece for Grid, Russian journalist Stanislav Kucher cited a well-known story from Putin’s childhood in which the future president cornered a rat with a stick in the stairwell of his apartment building, only for the animal to lash out and begin chasing him. The lesson is that you should never underestimate an opponent who has no choice but to fight back.

The fear now is that with his forces collapsing on the battlefield, Putin may feel himself backed into a corner. And given this president’s track record, he’s far more likely to escalate in such a scenario than to back down. One form of escalation came this week with the Russian government’s moves to annex territory and begin a mobilization of troops. Could the use of nuclear weapons be the next step?

For what it’s worth, U.S. officials say this still looks unlikely. Russia’s troops could still regroup and make a new push once reinforcements arrive. But Ukraine has also been retaking territory far more quickly than most experts anticipated. Things could get much worse for Russia before they get better, if they ever do.


The nuclear threat in Ukraine is often discussed in terms of “tactical” nuclear weapons, which generally refers to smaller, shorter-range weapons used to gain an advantage on the battlefield rather than inflict damage on an opponent’s society. As Grid has previously reported, this is somewhat misleading: There are few “tactical” targets for Russian nukes in this war. If they were used, it would be for coercive means, to pressure Ukraine and its allies into concessions or to prevent any counterattacks on territories it has gained. A 2020 study by the Center for Naval Analyses of Russian strategic thinking around nuclear weapons referred to this as “deterrence by intimidation.”

In a recent episode of the “War on the Rocks” podcast, one of that report’s authors, Michael Kofman, described how this might play out in practice: “It could look like demonstrative use of nuclear weapons over the Black Sea, or maybe let’s say Russian employment of a nuclear weapon against Snake Island, somewhere where there isn’t a lot of collateral damage. … That is only going to be used to be followed up by a coercive threat that if Ukraine doesn’t negotiate and if the United States doesn’t negotiate on behalf of Ukraine, that Russia will then proceed to use nuclear weapons in Ukraine.”

Would such an attack work, in terms of its strategic aims? Ukraine has already witnessed the wholesale destruction of several major cities without capitulating. And crossing the nuclear threshold comes with enormous downsides for Russia.

“To the extent they haven’t already been marked out as a pariah for the indefinite future, that would definitely do it,” David Shlapak, a senior defense researcher at the Rand Corporation, told Grid. “And it would be a very risky step for them to take, given that Ukraine is backed by nuclear powers that can climb the escalation ladder with them. I just don’t see a strong operational argument for them to use nuclear weapons.”

There’s been little study of the specific potential nuclear scenario Ukraine might now be facing, in part because Russia’s military performance has been much poorer than many experts anticipated. But Shlapak says nuclear options have come up in war games modeling Russia-NATO conflict. In these games, they tend to be used as “a way for the Russians to try to consolidate gains. So not for military effect, but rather for coercive effects. Having achieved their objectives on the ground, they now turn to NATO and say, ‘You can counterattack if you want to.”

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In Russia’s current, real-world predicament, nuclear weapons might be an absolutely terrible idea, one that would risk global cataclysm without accomplishing any strategic goals. The problem is, the same thing could have been said of Putin’s decision to launch this war in the first place. As Beatrice Fihn, executive director of the Nobel Peace Prize-winning International Campaign to Abolish Nuclear Weapons, recently tweeted, the notion that the risk of using nuclear weapons is simply too high “relies on always trusting Putin to do the right thing, always behave ‘rational,’ to play by the rules we expect him to play by, or that he never makes a mistake/misjudgment. I don’t trust leaders like Putin, therefore I don’t trust nuclear deterrence.”

Beyond Ukraine: a new nuclear world

In the early days of the nuclear era, it was assumed by many military planners that nuclear weapons would be used regularly on the battlefields of the future. The U.S. seriously considered using them in the Korean War. Thankfully, since then a taboo around their use has taken root, even as nuclear arsenals have grown.

In Ukraine, the world is witnessing something new: a long, drawn-out, high-stakes conventional war — meaning both sides are regular nation-state militaries with powerful high-tech weaponry — in which one side has nuclear weapons. Is such a conflict bound to go nuclear? The question has implications beyond Ukraine.

Biden’s latest warnings this week that U.S. troops would be used to defend Taiwan in the event of a Chinese invasion are a reminder of that. If countries believe that a war fought under the “nuclear shadow” can be kept limited to conventional weapons, that’s not necessarily a good thing: It might make them more likely to launch such a war. And even when all sides on the conflict are intent on keeping the war “limited,” escalation can take on its own momentum.

“Any country who is considering using nuclear weapons for a coercive purpose or tactical purpose is going to have to consider the ramifications of breaking the nuclear taboo,” Kathryn Boehlefeld, who teaches at the School for Advanced Nuclear Deterrence at the U.S. Air Force’s Air Command and Staff College, told Grid. “That said, because nuclear weapons exist, obviously they are always on the table. So it’s an inherently dangerous world.”

Thanks to Lillian Barkley for copy editing this article.

  • Joshua Keating
    Joshua Keating

    Global Security Reporter

    Joshua Keating is a global security reporter for Grid focused on conflict, diplomacy and foreign policy.