GEOFF BENNETT: Meantime, Democrats are increasingly divided on their presidential nominee.

More than 10 congressional Democrats today called for President Biden to step aside.

But his campaign insists he's staying in the race.

This morning, campaign chair Jen O'Malley Dillon said the president was aware that the last few weeks had been tough, but he remains committed to staying at the top of the tick ticket.

JEN O'MALLEY DILLON, Biden Campaign Manager: We have definitely seen some slippage in support, but it has been a small movement.

And you know this.

The reason is because so much of this race is hardened already.

The more and more people that see Joe Biden out there post-debate, they are reassured that he is in it to win it and he can do that.

GEOFF BENNETT: Our White House correspondent, Laura Barron-Lopez, joins us now.

So, Jen O'Malley Dillon says the president is in it to win it.

What else are you hearing from the campaign about his path forward?

LAURA BARRON-LOPEZ: Well, my Biden world sources are telling me that Trump's speech last night at the Republican National Convention emboldened them.

They feel like they got a boost from, that the morale saw a boost.

And they saw in that speech someone who they say is very beatable.

The rhetoric that he used, the mass deportations he talked about, the extremism when talking about immigration, they think that they can beat him.

And President Biden while recovering at Rehoboth issued a statement in response to that speech today, saying -- quote -- "I look forward to getting back on the campaign trail next week to continue exposing the threat of Donald Trump's Project 2025 agenda while making the case for my own record and the vision that I have for America."

The campaign also held an all-staff call today, where Jen O'Malley Dillon, the campaign chair, tried to boost morale on that as well, saying that, yes, it's been hard, but they are sticking in this and they're not going to be getting out of the race.

GEOFF BENNETT: Laura, why has this effort to push President Biden out of the race, why has this picked up steam?

Because this really subsided after the assassination attempt of former President Donald Trump.

LAURA BARRON-LOPEZ: Well, part of it was because of the assassination attempt that so many Democrats paused them coming out to call on him to step aside.

But we expect more lawmakers to come out and calling on him to withdraw.

And within the last 24 hours, as you noted, if it's been more than a dozen, including two senators who have said that President Biden should step aside and pass the torch.

And sources told me that we can expect more lawmakers tonight and over the weekend to come out and say that President Biden should step aside.

Despite that, there was some circling of the wagons today.

House Majority Leader Hakeem -- Minority Leader, excuse me, Hakeem Jeffries said that he still stands with President Biden.

The Hispanic Caucus political campaign arm, BOLD PAC, came out and formally endorsed President Biden.

But there was some notable comments from Senator Chris Coons, a key Biden ally, a senator from Delaware, who at an event in Colorado today said that President Biden is weighing who is the best candidate to win in November and that President Biden is hearing from a lot of people, colleagues and the public alike, so not definitively saying that President Biden was without a doubt staying in the race.

GEOFF BENNETT: And the Democratic National Convention, as you all know, that's not until late August.

I mean, how long can this go on?

What are Democrats telling you about that?

LAURA BARRON-LOPEZ: Democrats -- whether Democrats support President Biden staying in or think that he should go, they say that the situation is untenable, and a lot of them really want a resolution by Monday.

They want to come to a resolution.

A senior Democratic aide told me, though, that the dam feels like it's breaking and that, again, more and more are going to come out.

I spoke to Congresswoman Veronica Escobar, who supports President Biden staying in the race, saying that she's worried that, if he steps aside, the party will descend into chaos and that there aren't -- the colleagues that she talks to, she says that they aren't -- they haven't convinced her that everyone will rally behind Vice President Kamala Harris if President Biden were to step aside.

And so she really feels like there's a bit of separation from reality right now going on amongst her colleagues.

GEOFF BENNETT: So what other Democrats then is the party considering or are some lawmakers considering to replace President Biden on the ticket?

LAURA BARRON-LOPEZ: Vice President Kamala Harris is the first name that a lot of Democrats mention, including Congressman Jared Huffman, who today was one of the Democrats that called on Biden to step aside.

He said that he thinks there's widespread support for Vice President Harris and that those who are calling for an open convention are outliers.

But there are some Democrats and some donors who have mentioned names like Pennsylvania Governor Josh Shapiro or Michigan Governor Gretchen Whitmer.

So there's no clear consensus right now, Geoff, as Democrats still try to figure out what to do here when it comes to President Biden's nomination.

GEOFF BENNETT: All right, more to come.

Laura Barron-Lopez, thanks so much.

LAURA BARRON-LOPEZ: Thank you.