Joe Biden has presided over legislative deals that American presidents have sought for years, struggled with unpopularity yet led the Democrats to a historically strong performance in last year’s midterm elections, all before turning 80.

Now, in the coming months, Biden will probably answer a simple question: would he still want to be president at age 86? And, if so, is he prepared to take down Donald Trump – or perhaps another, possibly much younger, Republican candidate – to win a second term in 2024?

Should the answer be yes, Biden will make clear that despite many Americans’ wariness and the fact that he is the oldest president ever to occupy the White House, he is ready to continue leading the Democrats.

But if the answer is no, a vigorous battle to inherit his crown will ensue, with everyone from his vice-president, Kamala Harris, to his transportation secretary, Pete Buttigieg, expected to participate.

By all outward appearances, Biden currently plans to run for a second term.

“Watch me,” he replied in November, when asked to respond to one of the many polls that has found a majority of Americans do not want him to stand again. That same month, one of the biggest arguments against his candidacy – that his unpopularity would harm Democrats nationwide – was undercut when the party did much better than expected in the midterms.

“I think Biden’s running again,” said David Brock, a veteran liberal political operative. “Had the midterm turned out differently, we’d be in a different place where we’d be handicapping who was best to take on the Republicans, but I don’t think we’re in that moment now. I think we’re in a Biden moment.”

November’s elections were indeed a show of unexpected strength. The party in power typically does poorly in its first midterm, but the Democrats gained a seat in the Senate and only barely lost the House of Representatives to the Republicans.

Biden has not yet made his decision official, and there are still reasons to think he could decide that one term is enough. “The economy’s a question mark. His health is a question mark, international affairs is a question mark,” said Larry Sabato, director of the University of Virginia’s Center for Politics, who otherwise believes Biden is sure to stand again.

“He spent his entire adult lifetime running for president, and on the third try, he finally got there. Who would give it up under those conditions, who? Almost nobody,” Sabato said.

Biden won the Democratic nomination in 2020 after outmaneuvering a crowded field of candidates, his strongest challenger being the leftwing senator Bernie Sanders. As his re-election decision approaches, there are signs the party’s left flank hasn’t overcome their unease with Biden.

“We see Biden as a brake on the good things that need to happen,” said Jeff Cohen, a media critic and co-founder of the progressive group RootsAction. While Biden has pursued some policies popular with their voters, such as a partial student debt cancelation and provisions aimed at reducing America’s carbon emissions that were included in last year’s Inflation Reduction Act, Cohen views these as half measures.

His group has started a campaign, Don’t Run Joe, which is circulating a petition and airing television ads in early primary states Michigan, Georgia and South Carolina that encourage Biden to step aside.

“We need a bold, Democratic party leader with a bold agenda,” Cohen said. “Our feeling is that … anything less than a bold agenda, where Joe Biden is running again in 2024, and he’s seen as the symbol of the status quo, he could be defeated by one of these Republican faux-populists” like Trump, or Ron DeSantis, the Florida governor who is seen as a potential alternative among Republicans, though has not yet entered the race. Cohen expects that even if Biden does run again, he’ll face at least one challenge from the party’s left.

For its part, the Republican party is expected to do everything it can over the next two years to frustrate and undercut Biden, including by using the House’s powers of investigation to raise questions about how the White House handled the pullout from Afghanistan in 2021, and about the business dealings of the president’s son, Hunter Biden.

They will also continue trying to draw Americans’ attention to Biden’s gaffes – the message being that he is too elderly to lead. Brock, however, believes Biden could turn the situation around by casting himself as something of an old wise man.

“If it was couched properly, the age issue could become an asset,” said Brock, who recently founded Facts First USA, a group that plans to push back against the GOP’s investigation campaign. “What I would do is craft a campaign around the idea of trust, and age is part of trust. And that Joe Biden can be trusted … he’s proven he’s been able to achieve a lot.”

Biden hasn’t said when he will make his decision, but Sabato expects him to do so around when spring begins, to stop any rival Democrats from laying the groundwork for their own run.

Should he step down, any number of alternatives could emerge, from 2020 veterans like Buttigieg, Sanders and Harris to new contenders from the ranks of Democratic state governors, like Gavin Newsom of California, Gretchen Whitmer of Michigan, or Jared Polis of Colorado.

“The party feels like things are going well right now … there’s just no obvious reason to challenge him,” the Democratic political strategist Simon Rosenberg said of Biden. “And so I think that the nomination is his if he wants it, and if he doesn’t run, I think the Democrats will have a very vigorous primary and we will still be more likely to prevail in 2024 than the Republicans no matter who becomes the nominee.”