Russian President Vladimir Putin addressees the nation in Moscow on...

Russian President Vladimir Putin addressees the nation in Moscow on Feb. 24. Credit: AP

On Sunday morning, Russian President Vladimir Putin ordered his defense minister to place the country's "deterrence forces on high combat alert." This technical-sounding order left the normally unflappable Sergey Shoigu visibly uncomfortable — and with good reason: In the middle of the invasion of Ukraine, Putin had just ordered him to start readying Russia's nuclear forces for use.

The likelihood of a nuclear war, while still low, is rising. Putin's unprovoked war of aggression has, so far at least, not played out as he might have hoped, and this nuclear threat is unlikely to change the war's dynamics. If the conflict drags on, desperation could lead him to cross the nuclear threshold. Ukraine, the United States and its NATO allies will have to try to create an off-ramp for Putin to avoid that catastrophic outcome.

Putin's problem is clear. Russia's armed forces are making much slower progress than he likely anticipated, their losses are mounting, and his war appears to be proving unpopular at home. The West is unified and has agreed to levy truly severe sanctions, including against Russia's central bank. Right now, the best case for Russia would be the eventual defeat of Ukraine in a drawn-out bloodbath that leaves NATO more united and resolute than before. We can only speculate about Putin's worst fears, but given his public expressions of "disgust" over the killing of the Libyan dictator Moammar Gadhafi, he may worry about incurring the same fate.

Putin likely has some general sense that a nuclear threat, backed by Russia's vast arsenal, offers a way out of this quandary. But does it?

In the coming days, Russia's nuclear force posture may change in a way that indicates whether Putin aims to threaten the United States or Ukraine or both. One possibility is that Russia alerts its so-called strategic nuclear forces — those that can reach the United States — by, for example, dispersing its road-mobile intercontinental ballistic missiles (which are normally kept in garages) or loading long-range bombers with nuclear weapons. These actions would indicate that Putin seeks to threaten Washington.

If he were to do that, Putin might be implying that he would use nuclear weapons if the United States intervened directly, consistent with a warning he issued on Thursday in announcing his invasion (sorry, "special military operation"). Yet preventing the United States from entering the war directly — which President Joe Biden had already categorically ruled out before it started — won't provide a magic shortcut to defeating Ukraine's armed forces, which have held out by themselves so far.

Putin's remarks on Sunday, however, suggest a somewhat different purpose. Taken literally, they appear to imply that Russia will use nuclear weapons unless the United States and its allies lift "illegitimate sanctions" and stop making "aggressive statements." Perhaps Putin is also demanding that the United States and its allies stop providing equipment to Ukraine. If so, this threat is so outlandish — essentially "be nice to us or we'll nuke you" — that it won't be taken seriously. Indeed, the United States has, quite sensibly, not raised the alert level of its own nuclear forces, and Biden has publicly discounted Putin's threat.

Another possibility is that Russia may start to move the warheads for its nonstrategic delivery systems, those that cannot reach the United States, from their storage sites to the bases where these delivery systems are deployed. In this case, Ukraine would be the likely target of Putin's nuclear threat. However, as President Richard Nixon discovered in 1969 when he initiated the so-called Madman Nuclear Alert to try to force North Vietnam and the Soviet Union to make concessions at the negotiating table, it's very difficult to make the other side believe that you're willing risk Armageddon for anything less than the defense of your own territory. The fact that Putin claims this war is defensive won't make his threat more credible — every aggressor says the same thing.

In short, whether Putin currently realizes it or not, his nuclear alert is unlikely to help him win the war. But the danger of nuclear escalation is real even so. In fact, the danger is real precisely because Russia's nuclear threats are unlikely to work; as RAND Corp. analyst Samuel Charap put it, "an isolated, angry Putin" could end up "presiding over a grinding, existential conventional war and an economy devastated by sanctions." In this situation, Putin may feel that he has given Washington and Kyiv fair warning, and then resort to nuclear use, likely on the battlefield, in the hope it'll lead one or both of them to back down.

To avoid that situation, Ukraine, the United States and NATO should try to give Putin a face-saving way to end the war on terms that preserve Ukraine as an independent state — though it is, of course, ultimately up to Putin whether he takes such an off-ramp.

Ukraine's performance on the battlefield has been remarkable. However, Ukrainian President Volodymyr Zelenskyy surely understands that if he cannot negotiate a quick end to this war, Putin may level Ukraine's cities like he leveled Grozny in 1999-2000 or even use nuclear weapons. Kyiv and Moscow have already begun negotiations, though they ended Monday morning without a deal. Any future talks will presumably focus on the status of Donetsk and Luhansk and a possible Ukrainian commitment not to join NATO.

For there to be any chance of an agreement, the United States and its allies will have to lift the most punishing of the current round of economic sanctions — the freeze on Russia's central bank, which threatens to destroy the ruble. The whole point of sanctions, after all, is to lift them if your adversary changes its behavior. Washington and its allies should make clear to Moscow which sanctions they will lift as part of a cease-fire agreement. They should resist the inevitable calls to make sanctions relief contingent on the resolution of issues — such as the status of Crimea — that are not germane to the immediate conflict. They should also reup some of the security-building measures they presented to Moscow in January. For example, the United States and its allies could again offer Russia, subject to reciprocity, the right to inspect Aegis Ashore missile defense installations in Europe to verify that they cannot be used to fire offensive missiles.

It is deeply distasteful to identify incentives for Putin to back down after he launched an illegal war that will likely kill thousands of Ukrainians and rank-and-file Russian service members who had no choice but to fight. But unless one state annihilates another's armed forces, which Ukraine cannot do to Russia, ending wars always involves agonizing compromises. Ultimately, they are worse than the alternatives — which in this case, include a nuclear war.

James M. Acton holds the Jessica T. Mathews chair and is co-director of the nuclear policy program at the Carnegie Endowment for International Peace.

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