By Matthew Kroenig
Russia might use nuclear weapons to achieve its goals in the war in Ukraine—a risk that has only grown as Russian forces confront Ukrainian counteroffensives. Such nuclear use could advance the Kremlin’s military aims, undermine U.S. interests globally, and set off a humanitarian catastrophe unseen since 1945.
To deter such a potential disaster, the United States should issue public, deliberately vague threats of serious consequences for any Russian use of nuclear weapons and be prepared to follow through with conventional military strikes on Russian forces if deterrence fails.
Background: Russian nuclear use in Ukraine is possible
Following Russia’s further invasion of Ukraine this year, the United States and its allies and partners have responded with military aid to Ukraine, sanctions on the Russian economy, and reinforcements to NATO’s eastern flank. To date, the United States and its allies have ruled out direct military intervention against Russia.
Nuclear threats are core to Russia’s military strategy, and there is a nonzero chance that Russian President Vladimir Putin will order a nuclear strike on Ukraine.
Russia’s so-called “escalate-to-de-escalate” strategy calls for nuclear threats and, if necessary, limited nuclear use to compel the end to conflict on terms favorable to Moscow.
Putin has made a series of nuclear threats against the United States and the West, with the aim of preventing them from coming to Ukraine’s defense.
In addition, Russia has employed dual-capable weapons (which can carry both nuclear and conventional warheads) against Ukraine and conducted exercises with its nuclear forces.
Putin may believe that he could use nuclear weapons to compel the United States and the West to cease their support for Ukraine.
Russia has a wide range of options for conducting nonstrategic nuclear attacks by using one or more of the thousands of low-yield, battlefield nuclear weapons it already possesses. Russia could employ such nuclear weapons in a limited way against Ukrainian forces, bases, logistics hubs, and even cities.
Russian nuclear use would harm U.S. interests in the war in Ukraine and globally.
Such a strike could cause a humanitarian catastrophe, deal a crippling blow to the Ukrainian military, divide the Western alliance, and compel Kyiv to sue for peace.
It would also break a nearly eight-decade taboo on nuclear use. It may make future nuclear use more likely if states (e.g., China) perceive that nuclear weapons can help them achieve their goals without resulting in serious military retaliation from the United States and its allies. Further, it could cause nuclear proliferation if states fear that nuclear weapons might be used against them or if U.S. allies believe that Washington will not respond to a nuclear attack.
Recommendations for U.S. policy to prevent Russian nuclear use
To prevent Russia from employing nuclear weapons in Ukraine, the United States should issue a clearer deterrent threat. It could choose between vague or explicit threats issued publicly or privately.
At present, Putin may believe that he could use nuclear weapons without a significant Western response. A clearer U.S. deterrent threat would help disabuse him of that notion.
A vague threat (e.g., “Russia’s decision to use nuclear weapons in Ukraine would risk the gravest possible consequences”) has the benefit of conveying to Russia that there would be repercussions for nuclear use without committing the United States to a particular course of action.