What is a no-fly zone?

AS VLADIMIR PUTIN’S army closes in on Kyiv, and Russian rockets fall on Ukrainian cities, America and its allies are being asked to step in. On February 28th Volodymyr Zelensky, Ukraine’s president, repeated his earlier request for the West to “impose a no-fly zone over significant parts of Ukraine”. Some influential people agree. “Are we going to sit and watch while a world power invades and destroys and subjugates a sovereign nation?” asked Philip Breedlove, a former American general who commanded NATO forces until 2016, in an interview with Foreign Policy, a magazine.

The idea of declaring airspace off-limits is an old one: after the first world war Germany was prohibited from any sort of military aviation at all, under the Versailles treaty. But the modern no-fly zone dates to the 1990s after Sadam Hussein, Iraq’s then dictator, attacked Kurds in the north of his country and Shias in the south. America, Britain and France declared no-fly zones in the northern tip of Iraq and over the bottom half of the country. To enforce it, they flew around 225,000 sorties between 1991 and 2003 (France pulled out in 1996). Similar no-fly zones were enforced by NATO over Bosnia and Herzegovina between 1993 and 1995, and over Libya in 2011, as part of a war that eventually toppled Muammar Qaddafi, the country’s leader.

No-fly zones prevent a country from using warplanes to attack military targets or civilians on the ground. But that humanitarian benefit comes at a cost. Simply declaring airspace off-limits is not enough. The power that declares it has to patrol the area with its own planes and be prepared to fire at enemy ones—four Iraqi planes were shot down in the 1990s. To conduct such patrols safely, it has to be confident its planes won’t get shot down. And that requires identifying, jamming or destroying air-defence systems on the ground. “The reality of a no-fly zone is [that] it is an act of war,” says Mr Breedlove.

Going to war against Iraq and Libya was one thing. Doing so against Russia would be another. “It would essentially mean the US military would be shooting down…Russian planes,” warned the White House on February 28th. “That is definitely escalatory, and would potentially put us in a place where we’re in a military conflict with Russia.” A no-fly zone “would involve British fighter jets shooting down Russian fighter jets,” agreed Ben Wallace, Britain’s defence secretary, on March 2nd. He said it could drag NATO into the conflict and ultimately result in “a war against Russia, across the whole of Europe”. Jens Stoltenberg, NATO’s secretary-general, has said that the alliance has “no intention of moving into Ukraine, either on the ground or in the air”.

No-fly zones also have their limitations. The one over Bosnia struggled to stop helicopter flights, for instance. And while no-fly zones can prevent an adversary from using aircraft, they do nothing to stop them using other forces—like the huge convoy of Russian armour now 15 miles from Kyiv—for the same purpose. In the 1990s, unable to bomb Shias from the air, Saddam simply assaulted them from the ground as “US pilots enforcing the [no-fly zone] circled overhead”, observes Micah Zenko, an analyst. Partly as a result, he notes, every no-fly zone that America has ever imposed “was expanded to support military and political objectives that had nothing to do with how they were initially justified.”

Proponents of no-fly zones play down these risks. They argue that Mr Putin no more wishes to start a war with NATO than the alliance does with him. Some suggest that America could establish a partial no-fly zone over western Ukraine, far from the focus of Russia’s war. They point to the example of Syria, where Russia and America “de-conflict” their military presence so that their respective planes avoid flying at the same altitude or location as each other. A no-fly zone over western Ukraine might help Mr Zelensky establish an alternative government from Lviv, a western city, if Kyiv is lost. Perhaps precisely for that reason, the Pentagon says that Russia has shown no interest in deconfliction mechanisms for Ukraine. Russia wants a free run of its skies—and the West is unlikely to stop it.

Our recent coverage of the Ukraine crisis can be found here

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