SACHA PFEIFFER, HOST:

In the weeks since Russia launched its attack on Ukraine, many Ukrainian officials, civilians and journalists have repeatedly requested one thing.

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DARIA KALENIUK: We are asking for the no-fly zone.

UNIDENTIFIED PERSON #1: We ask about a no-fly zone over Ukraine.

UNIDENTIFIED PERSON #2: A no-fly zone. It has been arranged for other countries when people were dying.

PFEIFFER: But establishing a no-fly zone could come at a great price. Here's White House Press Secretary Jen Psaki speaking earlier today.

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JEN PSAKI: The no-fly zone requires implementation. It would require, essentially, the U.S. military shooting down Russian planes and causing a - prompting a potential direct war with Russia, something - the exact step that we want to avoid.

PFEIFFER: The U.S. and its allies have enforced no-fly zones over Iraq, Bosnia and Libya in recent decades. So what makes Ukraine different? We'll put that question to retired U.S. Air Force General Philip Breedlove, former Supreme Allied Commander of NATO.

Welcome to ALL THINGS CONSIDERED.

PHILIP BREEDLOVE: Hi, Sacha. How are you today?

PFEIFFER: I'm good. Thanks for making time for us. Would you explain how a no-fly zone for Ukraine would work practically speaking? What would or would not be allowed?

BREEDLOVE: Well, the first thing that I want to acknowledge is what Jen Psaki said is absolutely correct. A no-fly zone, if it is truly a military no-fly zone, is essentially an act of war because that means you are willing to enforce it, meaning those who violate it you would shoot at. And probably what would happen even before that is if there are defense systems in the enemy's territory that can fire into the no-fly zone, then we normally take those systems out, which would mean bombing into enemy territory. So no-fly zone is a big step, and we all acknowledge that.

PFEIFFER: But as we mentioned, the U.S. has enforced them in the past in other places - Iraq, Bosnia, Libya. Why is there reluctance to do so over Ukraine?

BREEDLOVE: Very simply, the opponent that we face today. The belligerent in this senseless war is Russia. We are very reticent to have a war with a nuclear power that is already talking about using nuclear weapons.

PFEIFFER: General, despite all the risks we have talked about, the risk that a no-fly zone could cause not just a war but a nuclear war, you've said that you support establishing one in Ukraine. Why do you support that?

BREEDLOVE: Well, we are now talking about the ability to do this possibly humanitarian no-fly zone. Russia has entered into a period of absolutely indiscriminate bombing of civilian targets and military targets in Kharkiv. So what are we in the West going to do to try to bring humanitarian assistance and relief to these people who are being senselessly attacked and indiscriminately attacked by Russia?

I have been accused of being a warmonger. I am anything but. I have five children - three by birth, two by marriage. They are all either in the uniformed services or working for the uniformed services. I understand what the costs of war are. And I'm not advocating war. But what I am advocating is, what are we going to do? Where does the thinking begin on how we help Ukraine?

PFEIFFER: How is a humanitarian no-fly zone different than a traditional no-fly zone?

BREEDLOVE: So for instance, in this case, 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. The goal of the humanitarian is essentially different than the goal of the military no-fly zone.

PFEIFFER: Would you still support the idea of a no-fly zone over Ukraine if you knew it would provoke Russia to use nuclear weapons?

BREEDLOVE: No. Nobody wants a nuclear war.

PFEIFFER: So then it's a gamble to put a no-fly zone into effect.

BREEDLOVE: Yeah, that's your word. That's not the word I would use.

PFEIFFER: What word would you use?

BREEDLOVE: It's a calculated military decision.

PFEIFFER: President Biden has been clear that he does not want the U.S. military fighting Russia. Given that he's stated that, how likely do you think it is that the U.S. and its allies would put a no-fly zone in place over Ukraine?

BREEDLOVE: Unlikely, but we have to have the conversation. How many Ukrainians have to die?

PFEIFFER: Right. It's a terrible question no one wants to answer.

BREEDLOVE: Yeah. And so we said that SWIFT was not on the table until SWIFT was on the table. We're saying now that the no-fly is not on the table. Who's to say what happens in the future? If we see the level of human destruction that we saw in Syria when they were barrel bombing cities or in Grozny and Chechnya - if we see that kind of destruction, who's to say that the no-fly zone doesn't come on the table?

PFEIFFER: That's retired U.S. Air Force General Philip Breedlove, former Supreme Allied Commander of NATO. Thank you again for your time.

BREEDLOVE: Thank you, Sacha. Transcript provided by NPR, Copyright NPR.