The case for and against establishing a no-fly zone over Ukraine

Ukrainian President Volodymyr Zelensky, facing an intense Russian invasion and the possibility of untold casualties and suffering, has called for the West to establish a "no-fly zone" over Ukraine to hold Russian forces at bay.

"I say every day, if you cannot shut the sky now, then give us the timeline when you will do it. If you now cannot provide the timeline, tell us how many people have to die," Zelensky said in a March 3 news conference. "I hope the sky will be shut down. If you don't have strength and courage to do that, then give me the planes. Wouldn't that be fair?"

Others, including a retired NATO supreme commander, U.S. Air Force Gen. Philip Breedlove, have echoed Zelensky’s call to use Western forces to prevent Russia from attacking Ukraine from the air, at least to provide humanitarian access.

"Maybe the humanitarian no-fly zone would only be over the western part of Ukraine such that we could get relief trains in and wounded and dying out to try to bring medical care to them," Breedlove told NPR, acknowledging that any "no-fly zone is a big step, and we all acknowledge that."

Still, the idea of a no-fly zone — the use of military assets to keep the enemy from flying over a given air space — has met with a cool reception from government and military leaders. Experts say caution is warranted for several reasons, including the possibility that it could lead to a global thermonuclear war.

Secretary of State Antony Blinken and NATO Secretary-General Jens Stoltenberg both made statements on March 4 that they considered a no-fly zone over Ukraine unrealistic.

"The only way to actually implement something like a no-fly zone is to send NATO planes into Ukrainian airspace and to shoot down Russian planes, and that could lead to a full-fledged war in Europe," Blinken said.

Russian President Vladimir Putin seemingly concurs, saying on March 5 that anyone who seeks to impose a no-fly zone would be "participating in the armed conflict."

Independent experts agree that a no-fly zone would be complicated.

"It would not be simple at all, and it would involve bombing Russian targets on the ground and shooting Russian aircraft out of the sky, and would almost certainly kill significant numbers of Russians," said Michael O’Hanlon, a foreign policy fellow at the Brookings Institution. "It would raise the distinct possibility or likelihood of retaliation and/or escalation. It is, to my mind, a very, very bad idea, and certainly not a straightforward or surgical one."

A Reuters/Ipsos poll taken in the early days of the war found that 74% of Americans, including majorities of Republicans and Democrats, said the U.S. and its allies should enact a no-fly zone in Ukraine. However, Reuters reported that majorities also opposed the idea of sending American troops to Ukraine or conducting air strikes to support the Ukrainian army, which a no-fly zone would require.

Here are some questions and answers about no-fly zones.

"A no-fly zone is not a military half-measure," wrote retired U.S. military officers Mike Pietrucha and Mike Benitez. "It is a combat operation designed to deprive the enemy of its airpower, and it involves direct and sustained fighting."

The U.S. or its allies have enforced no-fly zones on several occasions in recent years, including over Iraq from 1991 to 2003, over Kosovo in 1999, and over Libya in 2011. It involved tens of thousands of sorties, with no U.S. lives lost to enemy action.

The obvious difference is that Russia has a much more effective air force than any of those other countries.

"A no-fly zone over Ukraine would have to begin by suppressing the Russians’ integrated air defense system," said Stephen D. Wrage, a political scientist at the U.S. Naval Academy. (Wrage was speaking in his private capacity, not representing the views of the Naval Academy.) But even in the prior no-fly zones, this was not a simple task, and it would be far harder against Russia, he said.

Wrage said such a mission over Ukraine would require a base to launch thousands of flights, possibly from Poland, Germany, or both. "That spreads the war deep into NATO," he said, heightening the geopolitical risks.

For starters, establishing a no-fly zone over Ukraine would be expensive.

"Forty planes were launched for every patrol over Iraq, including high air cover, refueling tankers, electronic counter-measure planes, ground-attack planes and others," Wrage said. "Planes had to take off in pairs in order to get them all in the air before the first one off the ground needed refueling."

Friendly fire could also become a problem. "Shoulder-mounted and mobile missiles are hard-to-impossible to find or track," Wrage said. "Some of the thousands of stinger missiles already shared with Ukraine could be turned on NATO aircraft in error."

In some ways, a no-fly zone could actually provide Russia with a silver lining, because it puts U.S. or other Western forces at risk, allowing Russia’s leader Vladimir Putin to apply direct pain to the West as well as a stronger justification for his own fighting. "Putin’s planners might welcome a daily overflight of three or four dozen planes filled with American and NATO flyers," Wrage said.

And a no-fly zone would have an additional downside. It would undercut one of the most important things Ukraine has going for it: Its image as an unfairly besieged nation.

"A no-fly zone would end the brilliant contrast of valiant Ukrainian resistance to brutal Russian aggression," Wrage said. "There are better ways to express solidarity with the people of Ukraine."

The biggest reason to hold back on establishing a no-fly zone over Ukraine is that it would represent an escalation in the war. It would pit the United States, the United Kingdom, or France, or some combination, directly against Russia. Each of these countries are nuclear powers, which immediately puts a nuclear exchange, or a full-on nuclear war, into the realm of possibility.

"The main reasons the U.S. and its allies didn’t intervene against Russian invasions of Hungary in 1956 or Czechoslovakia in 1968 were the risks of direct military clashes between us and the Soviets," said Bruce Jentleson, a professor in Duke University’s Sanford School of Public Policy. 

Just days into the war, Putin made moves to signal that he’s well aware of the nuclear arms in his arsenal, including putting his nuclear forces on higher alert. But even if he hadn't done that, Jentleson said, "the escalation risks  would be there." 

Experts agree that it’s unlikely. They noted that it goes against President Joe Biden’s current policy, which is to avoid having Americans shooting at, or being shot by, Russian soldiers. "A no-fly zone breaks that clear line," Wrage said.

The more difficult decision would come if Russia eventually attacks a NATO ally, such as one of the Baltic states of Lithuania, Latvia, or Estonia, experts said. Members of NATO, including the United States, are bound by the treaty to protect other NATO members from attack.

"If Putin expands against NATO countries, Biden has said we will defend ‘every inch,’ which likely would mean direct military action, and some effort at air defense," Jentleson said. A no-fly zone could be part of that."