Speculation over whether Joe Biden can win in November – or serve four more years – continues to swirl amid concerns over his age and fitness.
The president’s team sought to quell unrest within the Democratic party in the aftermath of his debate performance last month – dubbed an “unmitigated disaster” by one Democrat and a “slow-motion car crash” by another.
But his gaffe at the NATO conference has made new headlines.
Just days ago, Biden insisted he would stay in the race and said the matter should be put behind him, but it remains to be seen if this line will hold.
The decision almost certainly rests with Biden himself – as well as those closest to him. But if he were to step aside, who might emerge as the frontrunner?
Vice president Kamala Harris
The Biden campaign is “quietly assessing the viability of vice-president Kamala Harris’s candidacy against Donald Trump in a new head-to-head poll”, Sky News’ partner network NBC News has reported.
Harris, 59, is the first woman to serve as vice president, the culmination (so far) of a career of firsts and breakthroughs.
She was born in Oakland to immigrant parents, her father came from Jamaica to become a distinguished economist at Stanford University and her mother was a cancer researcher who emigrated from India.
Regarded as a pragmatic path-breaker, Harris rose from local prosecutor to California’s state attorney general and then to US Senator, before being picked as Biden’s running mate in 2020.
She has high name recognition and the highest polling among Democrats who could seriously be considered a candidate, sources within the Biden campaign told the Reuters news agency.
She would also take over money raised by the Biden campaign and inherit campaign infrastructure, which would be helpful should she seek to run for president.
However, her personal approval ratings could prove a stumbling block. One recent poll gave Harris a 29% favourability rating, with 49% rating her unfavourably, and 22% saying they had no opinion or hadn’t heard of her.
Gavin Newsom
California governor Gavin Newsom, 56, is an established figure in the Democratic Party and among the names being floated as a potential successor – now or later.
However, he has repeatedly pushed back against calls to replace Biden, and said he would not run for president against Harris.
He has a background in business, encompassing restaurants and hotels, in his career before politics.
Newsom first came to national attention when, while the mayor of San Francisco, he and other city officials started handing out same-sex marriage licences – in direct violation of state law at the time.
His stock continued to rise and in 2019, he rode a landslide victory to his state’s top job, becoming Governor of California.
He is seen as a strong voice within the party and a talented debater, but his critics point to a poor record across a number of key issues in his state.
This includes high homelessness, drug problems, immigration issues, law and safety, high taxes, and more.
Gretchen Whitmer
Gretchen Whitmer’s swift ascent over the last two decades – from law school graduate to Michigan’s governor – has established her as a prominent figure within the Democratic Party.
Her status was solidified in 2022 with a decisive re-election and her party’s success in flipping both chambers of the state legislature, granting Democrats full control for the first time in nearly four decades.
Whitmer has been pushing the topic of abortion access in her role as co-chair of the Biden campaign, saying he is on the “right side” of the abortion fight despite his lacklustre performance in the recent debate on the question of reproductive rights.
She blames Trump for fuelling the political hatred that motivated a plot to kidnap and kill her that was foiled by the FBI in 2020.
When asked if she would consider becoming a candidate this year if Biden were to step down, she responded with a definitive, “No.”
Read more:
President Biden’s various gaffes over the years
George Clooney pleads with Biden to abandon re-election bid
Josh Shapiro
“Get s**t done” is Josh Shapiro’s slogan for how he wants to run Pennsylvania.
The governor is a rising star in the Democratic Party and is seen as one of a handful of governors who have been building their national profiles and positioning themselves for a 2028 run for the White House – before the issues with Biden emerged.
However, the 50-year-old son of a physician and former state lawmaker, county commissioner, and state attorney general, has backed the president.
“Here’s the bottom line. Joe Biden had a bad debate night, but Donald Trump was a bad president,” Shapiro said on CNN. He added Democrats should “stop worrying” and “start working”.
Michelle Obama
Well-known and popular from her time as first lady when her husband Barack Obama was president, there are many on the Democrat side who would love to see Michelle Obama as the party’s nominee.
Indeed, Trump supporters have fixated on the notion of Michelle Obama’s swooping in to replace Biden in an attempt to diminish the president’s political viability and stoke the GOP base.
An Ipsos poll found that she is the only hypothetical candidate to definitively defeat Trump head to head, and she also topped the charts in favourability among registered voters.
But would she be interested?
Earlier this year, her office told NBC News that she was not planning to run for office in 2024.
One of her aides pointed to her discussion last year with Oprah Winfrey to reflect her thinking – and why she would most likely never appear on a ballot herself.
“Politics is hard,” she said in the Netflix special. “And the people who get into it… you’ve got to want it. It’s got to be in your soul, because it is so important. It is not in my soul.”