At the NATO summit this week, President Volodymyr Zelensky of Ukraine lamented what he viewed as the failure of the United States and its allies to help establish a “no-fly zone in any way” over his nation. This follows his earlier pleas for a no-fly zone imposed by NATO or the United States soon after Russia began bombarding Ukraine. The Biden administration and NATO leadership as a whole have continued to reject proposals to impose a no-fly zone over Ukraine. They are right to do so.
Mr. Zelensky’s disappointment is, however, understandable. In just over a month of war, Ukrainians have suffered tremendously from horrific attacks by Russian missiles, artillery and aircraft. Russia’s onslaught hasn’t spared civilians. Its forces have destroyed hospitals and schools. Millions of Ukrainians have fled in fear.
Despite the egregiousness of such violence, a U.S.- or NATO-imposed no-fly zone over Ukraine is not the way to stop Russia’s aggression. It would have unclear humanitarian benefits while increasing, rather than lowering, the risk of war between the world’s two largest nuclear powers, the United States and Russia.
Mr. Putin, through words and exercises, has repeatedly raised the specter of mutually assured destruction since the start of this crisis. If a U.S.-Russian direct confrontation were to occur and Russia were to use nuclear weapons, even the detonation of a so-called lower-yield nuclear weapon would wreak enormous consequences and most likely provoke a NATO response. The conflict could escalate with terrifying speed. A 2019 simulation created at Princeton University suggests that what is intended as a warning shot from Moscow could, within hours, trigger a full-scale nuclear war with more than 90 million casualties.
Rather than run that risk for potentially little real effect, Western nations have chosen the more prudent path of supporting Ukraine in its fight as effectively as possible without getting directly involved.
The purpose of a no-fly zone would be to keep Russia’s planes from bombing civilians. To accomplish that objective would require threatening to shoot down Russian aircraft if they enter the designated zone and shooting down the planes if they fly in anyway. Enforcing a no-fly zone could also mean destroying Russian aircraft by attacking them on the ground, as well as attacking airfields and other support infrastructure.
In addition, NATO planes would most likely have to suppress Russian air defenses to protect their aircrews. This would involve additional NATO airstrikes on Russian forces on the ground, such as surface-to-air missiles and radar facilities. Given the range of some of Russia’s surface-to-air missiles, such as the S-400, some of the defenses covering Ukraine could even be located in Russia. Suppressing them could therefore require NATO to attack Russian forces on Russian territory. This is all true even for a so-called “limited” no-fly zone, one that covers only parts of Ukraine, an idea endorsed by a number of former U.S. officials. Mr. Putin has, unsurprisingly, said that he would regard any U.S. attempt to impose a no-fly zone over Ukraine as bringing the United States and its NATO allies into the conflict.
A war between Russia and NATO will be difficult to keep limited. Given Western conventional superiority and talk of regime change in Russia from a U.S. senator, war could easily be perceived as an existential threat for Moscow. In that case, and in line with Russian doctrine, it is not impossible that the Kremlin could green-light nuclear weapon use, including against air bases supporting any such no-fly zone. Even if officials deem this nightmare scenario not the likeliest outcome of more direct Western action, it poses cataclysmic dangers that cannot be ignored.
Setting the escalation risks aside, no-fly zones by themselves counter only threats from the air. They do nothing to protect civilians from ground-based threats like missiles and artillery. Bombs dropped from warplanes have accounted for some of the death and destruction Russia is inflicting upon Ukraine (Russia has in recent days ramped up its sortie rate to hundreds a day). But according to data collected by Action on Armed Violence, an advocacy group that focuses on the impact of armed violence, more civilian casualties have been caused by ground-launched artillery, rockets, and missiles than air-launched weapons.
Even the strikes that come from aircraft may come from planes far away, rather than overhead: the cruise missile barrage against the Ukrainian military base at Yavoriv was launched from aircraft that never left Russian airspace. A no-fly zone would not stop such threats. And when it becomes clear that such a zone is not enough, as happened in Bosnia in 1995, the United States may soon feel pressure to expand its military operation to strike additional targets on the ground, further drawing it into the conflict.
Indeed, past experiences reinforce the need for caution. Since the 1990s, the United States and its allies have imposed no-fly zones in northern and southern Iraq, Bosnia, and Libya. In none of those cases was the United States trying to impose a no-fly zone against a military with Russia’s capabilities, or one with the ability to retaliate with nuclear weapons. Moreover, all had mixed results when it came to protecting civilians.
In 1995, even with a NATO-imposed no-fly zone in effect, Serb forces perpetrated a genocide against Bosnian Muslims at Srebrenica and killed dozens of civilians in a mortar attack on Sarajevo’s Markale Market. After the no-fly zone’s failure to prevent such horror, NATO then expanded its intervention in Bosnia, carrying out additional strikes on ground-based threats to civilians such as Bosnian Serb artillery and arms depots. A similar situation could play out in Ukraine — only with the added risk of escalation.
This isn’t to say that the United States and its NATO allies should not be helping Ukraine to “close the sky” by other means. From the start of the war, Ukrainian air defenses have done serious damage to Russian aircraft. Although difficult to verify, according to Ukraine, its forces have destroyed 101 Russian planes and 124 helicopters as of March 23. They’re poised to get even more lethal: After Mr. Zelensky’s address to the U.S. Congress, the White House announced an additional $800 million in security assistance to Ukraine — adding to the anti-tank and antiaircraft weapons already provided — including some 800 Stinger shoulder-fired antiaircraft systems and switchblade drones, capable of both observation and attacks on targets such as Russian artillery. It is also reportedly exploring whether European allies could transfer Soviet-made S-300 long-range surface-to-air missiles to Ukraine.
It is important to recognize the significance of the measures the United States and others have taken to assist in the defense of Ukraine. The overt transfers of weapons to Ukraine — weapons intended to kill Russian forces — are themselves a remarkable and potentially escalatory step. So far, that does not appear to have crossed Moscow’s redlines for military retaliation against the United States.
Seeking to deprive Russia of airpower in the conflict would be an extraordinarily dangerous gamble with uncertain payoff. The Biden administration should remain resolute in rejecting such proposals, which, although presented as half measures to avoid direct war between the United States and Russia, are in fact tantamount to exactly that war. The United States and its NATO allies must continue to help Ukraine. But they must also do their part to avoid escalating that conflict, as the costs of doing so could well be unfathomable.