STORY: Worried Democrats, alarmed by President Joe Biden's debate performance against Republican rival Donald Trump, are openly questioning whether he should be replaced as their candidate in the 2024 election.

"The panic has continued."

:: Could Democrats replace Biden?

University of Virginia Center for Politics Director Larry Sabato said the process to replace a presidential nominee is clear but it wouldn't be easy:

"There is only one way for a nominee to be removed, and that is for the nominee to decide not to run before the convention, to open it up, to let the in this case, Democratic National Committee, set the rules for the convention, which would be an open convention with declared candidacies in advance, probably support from a certain number of state delegations, and then you let the convention work its will. It is the highest level of governance in either party. So the convention, in a sense, will serve as a primary electorate that has already voted. In order for Biden to step down. You would have to have a union of Barack Obama, Hillary Clinton, Bill Clinton, Nancy Pelosi, and they would have to all agree that he has to go in the interests of the country and in the interests of defeating Donald Trump. They would have to go to the White House and try to convince him, and he will be tough to convince. And they'll also have to try to convince Jill Biden. And that may be even tougher."

:: Who could replace Biden?

Sabato has a long list of possible replacements, but said there is no obvious top choice.

"Kamala Harris has to be on the list because she's the incoming vice president. I don't think she would be a particularly strong nominee. Governor Gavin Newsom, not just because he's governor of California, but because he has access to tons of money, which the new nominee would have to raise very, very quickly. There aren't many people who could do it. Governor Gretchen Whitmer would absolutely be in this mix, Michigan being one of the key swing states. Governor Pritzker of Illinois, who could self-fund. Governor Andy Beshear in Kentucky, Kentucky's deeply red, but Beshear has managed to be elected twice, which isn't easy for a Democrat in Kentucky. Governor Shapiro of Pennsylvania, who has become very popular very quickly, an articulate guy who comes across well and fits Pennsylvania, a key swing state, probably better than Joe Biden does and certainly better than Donald Trump does."

:: What happens next?

So far, Biden says he isn't going anywhere. His campaign held an "all hands on deck" meeting a day after the debate to reassure staffers that the 81-year-old was not dropping out of the race, according to two people familiar with the meeting.

"If this were anybody else but Donald Trump as the Republican nominee, this race would be over. It is only because Donald Trump is so controversial and so widely feared for what he may do, that Biden is still in the race, he still could win. Of course, you can also say that about Trump. If there were a new, vigorous, younger Democratic nominee, I think people would take that opportunity in a minute to keep Trump out."