The Washington PostDemocracy Dies in Darkness

A no-fly zone might help Ukraine. Or it might lead to nuclear war.

Some onlookers are frustrated that President Biden has ruled out directly attacking Russian forces. But it’s a necessary decision to avoid catastrophic escalation.

A Russian military convoy southeast of Ivankiv, Ukraine, on Feb. 28. (Maxar Technologies/AP)

Russian President Vladimir Putin’s invasion of Ukraine has galvanized the United States and its NATO allies, who are imposing increasingly powerful sanctions on Russia while shipping aid and advanced weapons to Ukraine. But not everyone is satisfied with these responses. Soon after the fighting started, Rep. Adam Kinzinger (R.-Ill.) tweeted that NATO should “Declare a #NoFlyZone over Ukraine” to disrupt Russian air operations and “give the heroic Ukrainians a fair fight.” Ukrainian President Volodymyr Zelensky has also called for a no-fly zone, while others have suggested that NATO might strike the slow-moving Russian convoy outside Kyiv.

But President Biden has made his policy clear, including in his State of the Union address on Tuesday night. “Our forces are not engaged and will not engage in conflict with Russian forces in Ukraine,” he said. Biden has reiterated this view consistently.

Why the firmness on this point? Biden’s goal, drawing on decades of practice during the Cold War, is to limit the risks of a nuclear exchange with Russia. As Biden told NBC News on Feb. 10, well before hostilities began: “That’s a world war when Americans and Russia start shooting at one another.”

Fighting a nuclear-armed country is simply not in the same category as going to war with the likes of Iraq or Serbia. And no one should imagine that imposing a no-fly zone would mean anything less than a major fight. To dominate the skies over Ukraine, the United States would not only have to engage any Russian aircraft operating there; it would also have to “suppress” Russian surface-to-air missiles on the ground in Ukraine and in the adjacent areas of Russia and Belarus.

Entering a shooting war with Russia would have profound consequences whose full extent cannot be foreseen. In all likelihood, NATO’s conventional superiority would soon present Putin with a stark choice: Either accept a humiliating defeat or unleash some version of the nuclear option that he is already brandishing. To limit that risk, most analysts judge that an armed conflict between the United States and Russia must be avoided, notwithstanding the commendable desire to do everything possible on behalf of an embattled Ukraine.

The West doesn’t want to push Putin toward using nuclear weapons. It might not matter.

The alternative now being pursued is a strategy honed during the Cold War years: proxy war. The United States and the Soviet Union learned to tolerate each other’s support for a foe, as long as this support did not mean joining the fight. As President John F. Kennedy’s national security adviser McGeorge Bundy wrote after leaving office: “The most important thing that the United States and the Soviet Union can do to stay clear of the ‘nuclear tornado’ is to see to it that they have no war of any kind with each other.”

This shared understanding did not emerge full-blown after the Soviet Union broke the American nuclear monopoly in 1949; it was a hard-won result of dangerous confrontations in Berlin, Korea and Cuba. A small direct clash did take place in October 1950, early in the Korean War, when American warplanes accidentally crossed the Soviet border, strafing an air base they believed to be in North Korea. This incident may have contributed to the Soviet decision to join the Chinese intervention in Korea that began the next month.

Soviet leader Joseph Stalin, who ultimately committed two full fighter divisions to the war, was cautious enough to insist that the planes be painted in Chinese colors and stay over Communist-controlled territory to avoid potential captures that would unmistakably demonstrate their identity. American pilots were jarred by the appearance of a tough new enemy that flew modern MiG-15 jets over a corner of North Korea that they came to call “MiG Alley.” Both sides chose to play it safe, keeping Soviet participation in the war a secret for many years afterward.

The turning point for these sorts of confrontations came in October 1962, when the Kennedy administration revealed that the Soviet Union had begun secretly placing nuclear-armed missiles in Cuba. President John F. Kennedy announced a “quarantine” of Cuba to prevent the arrival of additional Soviet weapons, if necessary by force. (The word “quarantine” was chosen because it was less suggestive of a state of war than “blockade.”) This act opened the 13-day crisis that brought the world closer to a nuclear exchange than ever before or since. Chastened, the two sides soon afterward created a leadership hotline to help defuse future crises and agreed to end nuclear testing in the atmosphere.

The superpowers also became more respectful of the perils of direct military confrontation. This attitude was evident in the choices of President Lyndon B. Johnson, who inherited many of Kennedy’s advisers. Despite “escalating” the Vietnam War with additional troops and massive bombing campaigns, Johnson refused to authorize the use of U.S. ground forces inside North Vietnam for fear of dragging in either the Soviet Union or China (which had tested its first nuclear weapon in 1964). His decision did not lead to an American victory, but neither did it lead to a general war with a nuclear-armed foe. Soviet forces stayed out, while China limited its participation to providing air defense and engineering support inside North Vietnam.

This process of restraint worked both ways. In the 1980s, the United States gave aid and advanced antiaircraft weapons to rebels inside Soviet-occupied Afghanistan but did not become directly involved. By then, proxy war had become a well-established norm between the superpowers.

Europe is showing that it could lead its own defense

Proxy wars involving nuclear powers are still dangerous, of course. Analysts worry that the Ukraine war could, even inadvertently, lead to a clash between Russia and NATO. Russian jets, for instance, supporting troops on the ground, could violate airspace over Poland, Slovakia, Hungary or Romania. Naval vessels and warplanes could also encounter each other in the Black or Baltic seas. With tensions running high, the risk of an unintended clash increases. And as arms flow into Ukraine, Russian attacks on the entry points could endanger personnel from NATO member states making deliveries. Still, these risks pale next to the dangers involved if NATO forces were to intentionally engage Russian jets, surface-to-air missiles or other Russian forces in and around Ukraine.

Western restraint may be frustrating. Putin’s campaign of conquest is an outrage, and preserving a democratic, independent Ukraine should be important to the entire free world. But an armed conflict that courts a nuclear exchange could lead to horrors of another magnitude entirely. To be blunt: If we are to safeguard the values of free societies, those societies must continue to exist. The best response to Putin’s reckless gamble with Russia’s fortunes isn’t an even more reckless gamble of our own.