JOHN YANG: Good evening, I'm John Yang.

The most significant challenge to Russian President Vladimir Putin is two decades in power lasted only about 24 hours.

But today there are questions about the long term consequences.

The streets of Moscow were quiet today as the last Russian troops left the capital to the south of Yevgeny Prigozhin and his Wagner mercenary group were cheered as they left Rostov-on-Don late last night.

They had captured the city just that morning.

The deal that diffused the mutiny calls for Prigozhin to live in exile in Belarus.

On NBC's Meet the Press Secretary of State Antony Blinken said the episode was a blow to Putin's authority.

ANTONY BLINKEN, U.S. Secretary of State: I think we've seen more cracks emerge in the Russian facade, it is too soon to tell exactly where they go and when they get there.

But certainly, we have all sorts of new questions that Putin is going to have to address in the weeks and months ahead.

JOHN YANG: Blinken also said it's unclear whether the Wagner fighters will return to the battlefield in Ukraine.

Angela Stent is a Russia expert.

She worked in the State Department during the Clinton administration and was a top intelligence officer during the administration of George W. Bush.

She's now a professor at Georgetown University.

Angela, you heard Secretary of State cracks in the façade.

Is it possible to tell how deep those cracks run?

How weakened is Putin now?

ANGELA STENT, Georgetown University: It's very difficult.

There's a lot that we don't know about what happened yesterday and what led up to it.

And it could just be the first act in a much longer drama.

But clearly, the fact that Prigozhin's troops were able to get within 200 kilometers of Moscow that they were as you just showed welcomed when they were in Rostov and they were cheered as they left.

That raised serious questions about the security services in Russia, about the military.

And about Putin's own future.

He certainly looks weaker emerging from this.

But then there's a lot that we don't know.

And let's wait and see where and when Prigozhin shows up again, isn't going to be Belarus.

We'll have to see.

JOHN YANG: You talked about the progress Prigozhin made on his advanced to Moscow.

What was the leverage or the -- was there a stick or a carrot that made him stop?

ANGELA STENT: So it's, again, we don't know a lot, but it's possible that he thought there would be more support for him from some of the top people in Moscow.

And it's possible when it became clear that that wasn't so that made him rethink what he was doing, because otherwise, it looks as if they could have reached Moscow pretty quickly.

And may, you know, and taken over, which is what people thought they would at the beginning of the day.

Or it's possible that a deal was made with him yesterday, where he was promised that both the Defense Minister and the Chief of the General Staff would be fired, which is what he'd been calling for, for months, saying they were incompetent.

But that, of course, hasn't happened yet.

So I think we'll have to wait and see.

JOHN YANG: Is a weakened Putin or at least a publicly chastised Putin, it's dangerous?

Do you -- is there concern that it'll do something rash, just to show that he's in charge?

ANGELA STENT: I think one could always have those concerns.

But I think there must be a lot of things going on that we don't know about right now inside the Kremlin.

It's, I mean, what's interesting is that none of his colleagues, not one of them has come out publicly and supported him, and that he did not announce the deal with Prigozhin yesterday, but his press secretary did, and he's been completely absent today.

Nothing, no public figures in Moscow.

So I think when gets to have to have some concern about what's going on inside the Kremlin, and how they going to deal with this.

JOHN YANG: As you say that he didn't say anything about this deal.

It was brokered by Belarus President Alexander Lukashenko.

Why do you think Lukashenko got involved?

ANGELA STENT: Well, I mean, that's what we're told.

And it may be true, they certainly put it out on all the media that he was the one who broke it.

And he's, of course a loyal ally of Putin.

He's very subordinate to Putin, and very dependent on him.

And maybe Putin wanted to make it look as if, you know, his hands hadn't touched this and left it to someone else to do it so that he wasn't actually himself negotiating with Prigozhin.

JOHN YANG: You said that there's a possibility that the Defense Minister and the General Chief of Staff may resign, which is what Prigozhin wanted, but did Prigozhin accomplish anything?

ANGELA STENT: I think what he accomplished was showing the Russian people to the extent that they knew what was going on, and the Kremlin, that he has quite a lot of support.

He has come out as a populist figure.

He actually said a couple of days ago, that the war in Ukraine was a big mistake, and that Ukraine wasn't threatening Russia.

And it was oligarchs in Russia who wanted to get their hands on assets in Ukraine.

And that was the reason for the war.

And the fact that that clearly does have a resonance, and then telling the Russian people that their sons and brothers are dying in this miserable fashion, and the children of the elite are sitting in the south of France and enjoying their cocktails.

I think all of that has a resonance.

And I think that should get everyone in the Kremlin thinking about what it means to continue this war.

JOHN YANG: And yesterday was tension between Russians, Russian against Russian, while the Ukrainians were sort of forgotten in this, what's the effect of this on the war?

ANGELA STENT: So I'm not sure that it does have that much of an effect on the wall unless Putin were really to rethink whether Russia should continue this law, which we haven't seen any signs of yet.

I think the Ukrainians will continue their counteroffensive and the Russians will continue defending against it.

So if there was an opportunity, it might have been yesterday if this had ended differently, but the way it's ended now, I think the wall will just continue.

JOHN YANG: Angela Stent of Georgetown University, thank you very much.