ARGUMENT: NUCLEAR DETERRENCEHow to Deter Russian Nuclear Use in Ukraine—and Respond if Deterrence Fails

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 US interests globally, and set off a humanitarian catastrophe unseen since 1945. Matthew Kroening writes for the Atlantic Council that 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.

Nuclear Weapons in Russian Strategy
Kroening writes that 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.

Preventing Russian Nuclear Use
Kroening writes that in order 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 US 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.

·  A more specific threat (e.g., “It shall be the policy of this nation to regard any nuclear attack against Ukraine as an attack on the United States, requiring a full retaliatory response”) would have greater deterrent value but limit US flexibility.

·  While a vague threat could be dismissed as cheap talk, a more specific threat runs the risk of drawing a “red line” that Washington cannot enforce, making a vague threat the better option.

·  These threats could be conveyed privately, but a public threat would likely be more effective in deterring Russia and assuring allies, as US credibility would be on the line for the world to see.

U.S. Response to Russian Nuclear Use
Kroening write that a clearer threat should be sufficient to deter a Russian nuclear attack, but Washington must be prepared to execute its threat if deterrence fails.

Retaliatory option 1: The United States could intensify its current approach: increasing sanctions on Russia, further isolating Moscow internationally, arming Ukraine with more advanced weapons, and redoubling efforts to militarily reinforce Eastern Europe.

Retaliatory option 2: The United States could respond with military force.

·  Option 2A: The United States could conduct a limited conventional strike on the Russian forces or bases directly involved in the attack. A more robust version of this option would be to join the war on Ukraine’s side.

·  Option 2B: The United States could use nuclear weapons to respond to and deter further Russian nuclear use in Ukraine.

Kroening concludes:

Given the costs and benefits above, the best US response if deterrence fails may be a mix of options 1 and 2A: an intensification of ongoing efforts to counter Russian aggression in Ukraine and a limited conventional strike against the Russian forces or bases that launched the nuclear attack.