What If Putin Uses a Nuclear Weapon in Ukraine?

From a Wall Street Journal opinion column by Walter Russell Mead headlined “What If Putin Uses  a Nuclear Weapon in Ukraine?”:

Ukraine scored a stunning victory in the Kharkiv region over the weekend. Routed Russian forces ditched valuable weapons and tons of badly needed munitions and supplies in a chaotic rush to safety. This signals a new stage in Vladimir Putin’s disastrous war. The Ukrainian army is better armed, better led and more committed to the war than its Russian opponents, and morale among Ukraine’s defenders will now be higher than ever.

Mr. Putin’s choices look bleak. As he struggles to stabilize the military situation while fending off critics at home, he must choose between accepting a humiliating defeat in Ukraine and doubling down in pursuit of a military victory that, as more Western weapons reach Ukraine’s energized defenders, looks very difficult to achieve.

Ukraine can take a moment to celebrate, and even gloat, over a hard-fought military success. The Biden administration deserves credit for leading the surge of allied support that made the Ukrainians’ extraordinary achievement possible. And supporters of peace and freedom around the world can rejoice that Mr. Putin’s wanton aggression has brought him to such an unhappy place. Yet Ukraine’s northern victory, however welcome, isn’t the end of the war. As Mr. Putin contemplates his options, we may be approaching a moment of maximum danger.

For Mr. Putin, the war in Ukraine began as what Council on Foreign Relations President Richard Haass has called a “war of choice.” Mr. Putin could have left Ukraine undisturbed and gone on to rule Russia for many years to come. But having chosen to start the war, he can’t afford to lose it. Radical Russian nationalists are already blaming him for the military failures in Ukraine. The Kremlin is no place for the weak, and the hard men who run Russia could turn on a politically wounded Mr. Putin in a heartbeat. Regardless of public sentiment across Russia, the people closest to Mr. Putin likely still want him to win the war.

The question is what Mr. Putin does next. If he can stabilize the military front until winter sets in, he has several months to prepare for the spring. He might use that time to organize a general mobilization, building a much larger conscript army for another year of conventional combat. But if the front doesn’t stabilize, or if he feels that public resistance to a general mobilization could endanger the stability of the regime, he might look to more drastic options, such as the use of nuclear weapons in Ukraine.

It is anything but clear how the West would respond. Allowing Mr. Putin to use nuclear blackmail to assert his control over Ukraine would be such a craven act that the moral and political foundations of the North Atlantic Treaty Organization would be shaken to the core—and nuclear-armed aggressors elsewhere would take note. Yet the obvious countermove, placing Ukraine under an American nuclear umbrella, risks the greatest nuclear crisis since John F. Kennedy and Nikita Khrushchev squared off over Cuba in October 1962.

So far, American policy has aimed at avoiding the binary choice between abandoning Ukraine and provoking a nuclear confrontation with Russia. For this policy to work, Washington needs a Goldilocks resistance from Ukraine: not so weak and cold that Russia wins a clear-cut victory, but also not so hot and successful that Russia, faced with a shattering defeat, resorts in desperation to its nuclear arsenal.

The Ukrainian advances in the northeast don’t yet force Mr. Putin to choose between nuclear blackmail and abject defeat. The relatively flat and open terrain of eastern Ukraine historically favors wars of movement, in which armies sweep back and forth over large distances without necessarily achieving decisive military results. That both Russia and Ukraine have stretched relatively small armies across a very long military frontier further increases the chance of breakthroughs. This isn’t World War I, in which massive armies were deeply entrenched along a largely static front line. And given shortages of troops and equipment, prudent commanders are unlikely to press Ukraine’s current offensive indefinitely forward.

Even so, the West needs to think about the unthinkable: If Washington’s Goldilocks scenario doesn’t materialize, and continued Ukrainian success turns Mr. Putin into a cornered rat, what then?

Difficult as it may be, President Biden should not blink. The use of nuclear weapons in Ukraine would imperil the security of our NATO allies and set an example of nuclear-backed aggression that would profoundly destabilize the international system. With the support of congressional leaders in both parties, Mr. Biden needs to tell Russia that a nuclear attack on Ukraine would be an act of war against the U.S. If Vladimir Putin chooses the path of Nikita Khrushchev, Joe Biden needs to stand like JFK.

Walter Russell Mead is the Ravenel B. Curry III Distinguished Fellow in Strategy and Statesmanship at Hudson Institute, the Global View Columnist at The Wall Street Journal and the James Clarke Chace Professor of Foreign Affairs and Humanities at Bard College in New York.