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.

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.

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.

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.

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?

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

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

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?

“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.”

Beyond Ukraine: a new nuclear world

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.

“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.”