Let's turn now to our White House correspondent, Laura Barron-Lopez, in Washington for more on those calls for President Biden to drop out of the race.

Laura, what's been the Biden campaign's response to all of this?

LAURA BARRON-LOPEZ: I asked a senior Biden adviser about all of these calls today, Geoff, and they texted back saying, he is the nominee of the Democratic Party and plans to win in November.

The campaign is not budging on this, Geoff.

And deputy campaign manager Quentin Fulks in Milwaukee today said that they are not considering any scenario where President Biden is not at the top of the ticket.

QUENTIN FULKS, Biden Principal Deputy Campaign Manager: I don't want to be rude, but I do not know how many more times we can answer that.

Joe Biden has said he is running for president of the United States.

Our campaign is moving forward.

We're drawing a vision and a contrast between that of Project 2025 and what we have seen for the past three days here in Milwaukee, the extreme agenda of Republicans, and that's where our focus is.

LAURA BARRON-LOPEZ: So even though some sources close to the campaign tell me that a lot of staffers there are anxious and waiting for a shoe to drop, publicly, the campaign is holding its ground.

AMNA NAWAZ: Laura, we know you have been talking to other Democratic sources as well.

What are you hearing from them about these efforts to get President Biden to step aside?

LAURA BARRON-LOPEZ: A number of the Democrats that I spoke to today, Amna, whether they were lawmakers or donors or party operatives, say that the next 72 hours are going to be critical, that they want to see some type of movement or resolution.

And I was speaking to one Democratic lawmaker today who said that they may very well come out and break with Biden by Monday, because they want to see some type of decision here.

And other Democratic sources that I talk to say the train has ultimately left the station for lawmakers, that they think that it is time for President Biden to step aside.

And a lot of them, some of their hesitancy comes from the fact that they want him to make that decision and they want him to make the announcement without having to come out publicly and pushing him to do so.

One other Democratic lawmaker that I was talking to today, Amna, said that they were getting calls from big Democratic donors in over the past few days saying that they want President Biden to step aside.

And those donors were telling that lawmaker that there should be an open convention.

Now, an open convention is something that a lot of lawmakers do not want and a lot of other Democrats do not want.

And it seems as though they'd like people, if President Biden makes this decision, to rally behind Vice President Kamala Harris.