JOHN YANG: Good evening.

I'm John Yang.

With support from Democrats are rolling by the day President Biden says he's dropping out of the presidential race and endorsing Vice President Kamala Harris to be his party's nominee.

And a letter posted on his account on X, he wrote, while it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as president for the remainder of my term.

Vice President Harris issued a statement saying, my intention is to earn and win this nomination.

Mr. Biden said he addressed the nation leader this week to more fully explain his decision.

For now he remains in isolation at his beach house in Delaware with COVID.

Now Laura Barron-Lopez covers the White House.

Lisa Desjardins covers Congress and the Trump campaign and Domenico Montanaro, Senior Political Editor and correspondent for NPR.

Lisa, Laura, rather, I'm going to begin with you.

How did we get from defiance to standing down?

LAURA BARRON-LOPEZ: Ultimately, as the weeks had gone on, John since the January 27.

Debate, President Biden was losing support every single day he was losing support from leaders in Congress.

He was losing support from Democrats in Congress.

He was losing donors.

And all of that combined, ultimately made it really untenable for the President to hold his position.

Even though his campaign aides his campaign co-chair Jen O'Malley Dillon, as well as President Biden and those around him continued to say he was in it he was not going to back out of this race.

But lawmakers and a lot of Democrats across the board had ultimately said that they wanted a decision from him by this coming Monday, Sunday evening.

Today, he says that he's not going to run for reelection, endorses Harris.

And already I'm told that Vice President Kamala Harris was making calls to governors to members to other people across the party apparatus to make clear that she is trying to earn this.

And we also saw that both a Bill Clinton and Hillary Clinton endorsed her.

Notably though Barack Obama, the former president did not specifically endorse her saying that he thought that the party would ultimately come to its own decision through a healthy process.

JOHN YANG: What do we know about the circle of advisors around the President as this process went on?

LAURA BARRON-LOPEZ: So we know that as the President had become also isolated with COVID, and as the weeks have gone on, since the debate, his circle of closest advisors had also started to shrink, and namely, the people that were constantly speaking to him and relaying what they were hearing from other members of the party to him were Steve Ricchetti, senior adviser to the President, as well as Mike Donilon, another longtime senior adviser to the President.

And Steve Ricchetti is also very close with members of Congress, John, and he was being told by a lot of members of Congress that this was not sustainable, that members of Congress thought that it was time for President Biden to step aside.

And so ultimately, at the end of the day facing all of that fallout from his party and the pressure campaign, the President does decided that it was time to allow someone else to step forward.

JOHN YANG: Pressure from Congress, Lisa Desjardins, what are we hearing from Republicans in Congress and from the Trump campaign?

LISA DESJARDINS: The Trump campaign quickly came out with a statement I posted on social media first, which former President Trump said that Biden was not and is not fit to serve.

I raise that because we have seen these resignation calls from other top Republicans, including House Speaker Mike Johnson, saying if he is not able to campaign that President Biden should also step aside because he may not be able to run the country.

Now, Democrats completely disagree with that.

But Republicans have been preparing this message for a while since that disastrous debate for President Biden.

Now, essentially, Republicans are quickly now turning to Harris.

They have been building files on her of course, since she was nominated for vice president.

But now as a potential nominee, they are looking at where she does well and where they might do well against her.

Sources close to Trump campaign world and the Trump campaign PACs tell me that Michigan, Wisconsin and Pennsylvania are three states that they think were Harris does, at least as poorly in their words or worse than Biden, they would like to pick up those states.

Those also, of course, are states where they think that perhaps new nominee vice presidential nominee J.D.

Vance could do well.

But you know, out of all of this, they are already launching an ad against Harris.

Look at this one from a PAC affiliated with Donald Trump.

WOMAN: Kamala was in on it, she covered up Joe's obvious mental decline.

KAMALA HARRIS, U.S. Vice President: Our president is in good shape, and good, tireless, vibrant, and I have no doubt about the length of the work that we have done.

LISA DESJARDINS: Something else that's important about this is I have sources in House Republican leadership and elsewhere telling me, we should expect investigations in the House immediately into this topic.

And also, by the way, they may extend the congressional session in the House, which would be a problem for frontliners on both sides, including Democrats.

JOHN YANG: Domenico, what does this do to the Democrats?

What's next for them?

They're just -- the convention is just weeks away, and a virtual Roll Call is even closer?

DOMENICO MONTANARO, Senior Political Editor and Correspondent, NPR: Well, politically, it's a pretty smart move to make this announcement if President Biden was going to make this announcement today, because it helps potentially to blunt any possible bounce that Donald Trump might have had out of the Republican National Convention, when we always see a Republican or Democratic candidate get some kind of a bounce out of that.

So Kamala Harris has a lot to prove in the next couple of weeks to be able to step up to the plate, so to speak, show that she has the vigor, the competence, that's opposite from what they saw with Joe Biden.

And that was the biggest problem was people saw how Joe Biden performed in that debate on the 28th, on June 27.

And Democrats, Harris on fire because they just thought that this was somebody who could not carry the message forward.

Kamala Harris as a candidate in 2019, struggled so much.

She didn't really seem to have a core.

She wanted to build herself as a problem solver.

But now she has a record to run on essentially, having served with President Biden, and now the party is going to be looking to her to be able to take that democratic message forward, if she indeed is the nominee, and likely will be as we're hearing from our sources.

JOHN YANG: Well, let me ask you about that.

This party, the Democratic Party has been split in the last couple of years between moderates and sort of more liberals.

Is the party going to fallen behind Harris?

Or is she likely to get a challenge?

DOMENICO MONTANARO: Well, I mean, you have to get 300 signatures from other delegates to be able to get on to a ballot at the Democratic Convention, Joe Biden has some 3,900 delegates already on his side.

Certainly his endorsement matters quite a bit with those delegates.

And we're seeing already a lot of statements out from people backing Harris.

So if she does get a serious challenge, it might actually be a good thing for her because she's likely to still win the nomination, and it would show she has some insight or political skills, that would certainly help her on her way.

Of course, if she doesn't get a serious challenge, then it shows the Democratic Party unity already.

So, we'll see what winds up happening.

There's certainly a lot of people with their eyes set on 2028.

There is a potential opportunity here for Democrats to be able to potentially gain a geographic advantage, because when you think about the people who might be a potential Harris, VP, there are some swing state, you know, candidates or swing state governors who might be a possibility or senator and think about somebody like Josh Shapiro in Pennsylvania, somebody like Mark Kelly, the senator from Arizona, both swing states, both places where Joe Biden, since that debate, has seen his poll numbers really crater somewhat.

And that's what really drove this decision by so many people concerned about whether or not Democrats could win in these swing states.

JOHN YANG: The next nominee is going to have to choose a vice presidential nominee.

I know, Laura, you've got reporting on that.

LAURA BARRON-LOPEZ: Yes.

So the names that I've been hearing the most from Democratic sources in terms of who could be a vice presidential pick for a presidential nominee Kamala Harris.

If she were to win the nomination our Pennsylvania Governor Josh Shapiro.

He's on the shortlist as well as North Carolina Governor Roy Cooper and Kentucky Governor Andy Beshear.

Of course, names like Mark Kelly have also come up which Domenico mentioned, as well as Governor Gretchen Whitmer, who's the governor of Michigan.

But those three ones that I named are the ones that I hear the most in terms of who they think would be best paired with Kamala Harris.

And also, if you look at those first two, Pennsylvania, North Carolina, key swing states, people that could potentially help Harris in those key states.

Now, of course, again, Harris doesn't have the nomination yet.

And there are some Democrats who want an open process, including former Speaker Nancy Pelosi who voiced that I was told in meeting with California Democrats a week or more ago, and so other names that have come up as potential nominee for president again, Gretchen Whitmer of Michigan as well as Shapiro of Pennsylvania.

Gavin Newsom also occasionally comes up from California.

But right now, it appears as though the majority of the party very quickly is rallying behind Harris.

JOHN YANG: Domenico, I want to ask you to wrap this up.

I mean, the Biden campaign wanted an early debate to try to change the direction of the campaign.

Well, they've done it in a way I think they've succeeded beyond their wildest dreams, changing the direction.

Give us a sense of your - - your sense of the state of this race right now.

DOMENICO MONTANARO: Well, certainly Trump has the edge.

He's ahead in a lot of the swing states all seven when I did a review of the polls this morning.

He certainly had anywhere from two to seven points in those states.

Now, can those numbers be made up?

Absolutely.

And certainly this pick is going to inject a degree of enthusiasm with Democrats, when you've seen a president with really probably the worst three-week stretch of any presidential candidate possible with maybe the worst debate performance in history, a solid Republican National Convention, where Trump's party showed the heavy degree of unity and confidence, and then three Biden getting COVID this past week, it really just played into the narrative that he's too frail to continue on as a candidate for four years.

I think this does change the narrative, though, because you have a younger candidate, if it is Kamala Harris or anybody else, and I already hear Democrats saying, hey, we can't have a candidate who's going to be 83 years old by the end of their second term if Donald Trump does win the presidency.

So already sort of inverting the narrative on Trump.

JOHN YANG: Domenico, Lisa and Laura, thank you all very much.

DOMENICO MONTANARO: You're welcome.