Since Russia launched its most recent invasion of Ukraine in February, Moscow has threatened—sometimes subtly, other times explicitly—nuclear escalation should the war not go its way. Ukraine and the West have to take such threats seriously. But the Kremlin also needs to take their probable responses seriously and would have to weigh the substantial risks and costs of using a nuclear weapon.
Shortly after Russian forces assaulted Ukraine on Feb. 24, Vladimir Putin ordered a “special combat readiness” status for Russian nuclear forces. But it’s unclear what that means since the Pentagon has consistently said it sees no change in Russia’s nuclear posture. The alert may have amounted to little more than additional command post staffing.
Since then, Russian officials have made implicit nuclear threats, such as Putin’s reference to using “all the forces and resources” Russia has to defend the Ukrainian territory he claims to have annexed on Sept. 30. Other Russians have voiced more overt threats. Former president Dmitry Medvedev on Sept. 27 “imagined” Russia using a nuclear weapon against Ukraine. The rhetoric has increased as the Russian army has suffered setbacks on the battlefield.
The war is clearly not going as the Kremlin hoped. The February Russian attack suggested objectives of quickly taking Kyiv and occupying as much as the eastern two-thirds of Ukraine. The Russian army failed to achieve either goal and quit northern Ukraine at the end of March.
In September, the Ukrainians launched counteroffensives in the east and south. The Russians retreated, yielding large tracts of territory to Ukrainian liberation. Putin ordered a mobilization, but an influx of poorly trained and equipped soldiers will hardly help.
Russia’s declining military fortunes have raised the question of whether Putin and the Kremlin might use a nuclear weapon against Ukraine. The goals would be two-fold: get Kyiv to capitulate, and persuade the West to end its military assistance to Ukraine. Such decisions would allow the Kremlin to snatch some kind of victory from what increasingly looks like a debacle.
However, the Russians would have to calculate what the situation might look like after a nuclear detonation.
A nuclear strike would achieve relatively little on the battlefield. The Ukrainian army does not mass forces in a way that would create an inviting target for a nuclear attack.
Moreover, the shock of the first nuclear attack in more than 75 years likely would not secure the capitulation Moscow wants. The Ukrainians understand what Russian victory means: summary executions, mass arrests, torture chambers, filtration camps, and loss of independence. Russian escalations—such as indiscriminate missile strikes on cities—have only hardened the Ukrainians’ will to resist. They would almost certainly fight on after a nuclear attack.
The Kremlin would have to consider international reactions. Russia would probably lose India, most likely China, and the rest of the Global South, who thus far have sought to remain neutral. Moscow would face broad international condemnation, Putin would become a global pariah, and other states could join in applying sanctions against Russia.
The Kremlin also has to weigh how the West would react. Western leaders have made clear their response would carry “extraordinarily serious” consequences for Russia. While officials have avoided specifics, the consequences could include an upsurge in the flow of arms to Ukraine, likely with an end to restrictions barring their use against targets in Russia proper. Consequences could also include military action by NATO members, such as conventional air and missile strikes on Russian forces in Ukraine.
This is the gamble the Kremlin would face. It would hope that public fear in the West would restrain the Western reaction. That might—might—prove a winning bet, but it more likely would prove a loser.
Western leaders have compelling reasons to support Ukraine and have publicly staked out their position in support of Kyiv. They would have to ask themselves: would caving in to Russian nuclear use in Ukraine not invite further nuclear threats and attacks from Russia and elsewhere in the future?
Russia could find itself in a shooting war with NATO, when the bulk of its ground forces can barely cope with Ukraine. Having opened Pandora’s box, the Kremlin would confront the unpredictable and catastrophic consequences that nuclear escalation could bring to Russia.
It makes little sense for the Kremlin to run that risk in a conflict that is not existential. Russia can lose this war—that is, the Ukrainian military could drive the Russians out—and the Russian state will survive. The Ukrainian army will not march on Moscow.
A rational actor in this case would conclude that the risks and costs of using a nuclear weapon are simply too high. Putin seems a rational actor, though he also seems more emotional today than in the past, which may cloud his calculation of risks and costs. And he has made many miscalculations, beginning with his disastrous decision to invade Ukraine.
Would he miscalculate again? That is the key unknowable. The hope is that rationality would prevail, and that senior political and military leaders in Moscow, who may not be so obsessed with Ukraine, would come down on the side of caution.
The nuclear threat understandably raises a frightening prospect. However, it is important to remember that Putin does not want a nuclear war. He wants Ukraine and the West to think he is prepared for nuclear war, hoping to intimidate them into backing down. Western leaders have to respond carefully but must also bear in mind the risks that ensue should they cave.