Could Democrats replace Biden as their nominee?

Washington is abuzz with fresh concerns about President Joe Biden’s fitness after a special counsel report released Thursday raised questions about his memory.

But Democrats have rallied around Biden and despite the fantasies of some pundits and anxious Democrats, the president is almost certain to be the Democratic Party’s nominee as long as he wants.

Both parties have moved away from the era when insiders in proverbial smoke-filled rooms could be kingmakers at the national conventions, and Biden has dominated every primary he’s competed in thus far.

No prominent Democrats have called for Biden to step aside and there's no known serious conservations about it.

“The Democratic Party is united in supporting President Biden, who will be his party’s nominee this fall and will make Donald Trump a loser a second time this November,” said Biden campaign spokesperson Daniel Wessel in a statement to NBC News.

In the modern era, a national party has never attempted to adversarially replace their nominee in part because they know it would likely fail. The issue came before both parties in 2016, but neither took such drastic action.

The “Access Hollywood” tape provoked some prominent Republican leaders to call for ditching Donald Trump, but then-RNC Chairman Reince Priebus said, “No such mechanisms exists."

Meanwhile, then-interim DNC Chair Donna Brazile wrote in her memoir that she “nearly replaced" Hillary Clinton after the candidate collapsed during a Sept. 11 memorial service, before ultimately concluding, “I could not make good on my threat to replace her.”

Still, the DNC Charter does make provisions in case the party’s nominee is incapacitated or opts to step aside, and an anti-Biden coup at the convention is theoretically possible, if highly unlikely. So how would it work?

Is it too late for another Democratic candidate to get into the race?

Only a small handful of states have held Democratic presidential primaries thus far. But there is still not enough time for a new candidate to enter the race and beat Biden outright.

Filing deadlines for about 80% of upcoming contests have already passed and cannot be easily changed since they are set in each state. There are not enough delegates at stake in the remaining contests where ballot access is still open to win a majority.

Of course, a Democrat could opt to run as a write-in candidate (though not every state allows write-ins). And Democratic Party rules can be changed. As private organizations, the Democratic and Republican National Committees are legally given a wide berth over how they select their nominees.

But Biden essentially controls the national party, as is standard practice for whichever party controls the White House.

Any changes to the party’s nomination rules would go through the DNC’s Rules and Bylaws Committee, stacked with Biden allies, which essentially rubber-stamped his controversial new 2024 presidential primary calendar putting South Carolina ahead of New Hampshire, even though the committee was not previously expecting to do that until the night before the vote.

What happens if Biden drops out before the convention?

Biden has said he will remain in the race and there is no indication otherwise, but the only plausible scenario for Democrats to get a new nominee would be for Biden to decide to withdraw.

He could do so while serving out the remainder of his term in the White House, as Lyndon Johnson did in 1968.

If Biden were to drop out between now and August, it would most likely create a free-for-all at the Democratic National Convention in Chicago in August.

If Biden calls it quits before he wins the majority of the Democratic delegates, it likely wouldn't make a difference. Any new candidate who tried to enter the race would be unlikely to get on enough of the remaining ballots and therefore couldn't win enough delegates.

Ultimately the decision would likely come down to the convention delegates who were initially pledged to Biden.

It takes a majority of the roughly 4,000 pledged delegates to win the party’s nomination. Under recent reforms, the party’s more than 700 superdelegates — Democratic lawmakers and dignitaries — are allowed to vote only if no one wins a majority of pledged delegates on the first ballot, so their votes could be crucial in a contested convention.

Biden would have some influence over the pledged delegates he won through the primaries, but ultimately, they can vote as they please.

His long-shot primary challengers, Rep. Dean Phillips, D-Minn., and self-help author Marrianne Williamson, who suspended her campaign this week, have won no delegates so far. And simply having run won't mean that they move to the front of the list in the event of a vacancy.

Could Democrats replace Biden against his will?

There’s no evidence the party would entertain a change without Biden’s consent. But even if they did, there is no mechanism for the national party to replace a candidate before the convention and certainly no way for them to anoint a chosen successor.

If large swaths of the Democratic Party lost faith in Biden, delegates to the national convention could theoretically defect en masse. Of course, they were chosen to be delegates because of their loyalty to Biden and have pledged to support him at the convention.

But, unlike many Republican delegates, Democratic delegates are not technically bound to their candidate. DNC rules allow delegates to “in all good conscience reflect the sentiments of those who elected them,” providing some wiggle room.

The party’s charter does contain provisions to replace the nominee in the event of a vacancy. The measure is intended to be used in case of death, resignation or incapacitation, not to replace someone who has no desire to step down.

That was the measure Brazile considered invoking after Clinton collapsed two months before the 2016 election.

In her memoir, released a year later, Brazile wrote that she was worried “not just about Hillary’s health but about her anemic campaign ... so lacking in the spirit of fight.”

“Perhaps changing the candidate was a chance to win this thing, to change the playing field in a way that would send Donald Trump scrambling and unable to catch up,” she wrote, adding that aides to other would-be candidates contacted her, including chief of staff to then-Vice President Biden.

But after less than 24 hours of consideration, Brazile realized the idea was untenable without Clinton’s cooperation and likely to only divide her party.

Current DNC Chair Jaime Harrison is a longtime Biden ally who serves, essentially, at the pleasure of the president. And the national party has certainly given no indication it's anything but fully behind the president’s re-election.

What happens if Biden withdraws after the convention?

To fill a vacancy on the national ticket, the DNC chair can call a “special meeting” of the full Democratic National Committee, which includes about 500 members. On paper, at least, all it takes is a majority vote of those present to pick a new presidential and vice presidential nominee. But that process would likely be anything but smooth, and be filled with behind-the-scenes jockeying and public pressure campaigns.

If a vacancy were to occur close to the November election, however, it could raise constitutional, legal and practical concerns. Among other issues, ballots have to be printed well in advance of the election and may not be able to be changed in time.

Would Kamala Harris replace Biden?

If Biden were to relinquish the presidency, Vice President Kamala Harris would automatically become president — but not the Democratic Party’s nominee. Nor would she necessarily be the nominee if Biden withdrew from his re-election bid while remaining in the White House.

She might be politically favored, but party rules give the vice president no major mechanical benefit over other candidates.

Biden’s delegates would not automatically transfer to Harris and the convention holds separate votes on nominees for president and vice president. So she would still need to win a majority of delegates at the convention.

If the top of the ticket was vacated after the convention, she would still need to win a majority of votes at the special meeting of the DNC.

That is all, at least, under current party rules. But a vacancy at the top of the ticket is the kind of dramatic moment that might lead party leaders to revisit them in the name of easing the transition. Harris has some close allies in key places at the DNC, including the co-chair of the party’s Rules and Bylaws Committee. But nothing would likely happen without a fight.

This article was originally published on NBCNews.com