Who is in, who is out and who is still thinking about a US presidential election run?

Democratic US President Joe Biden announced his re-election campaign on Tuesday, as most Republican hopefuls were still trying to decide whether to challenge former President Donald Trump.

Here is a list of declared candidates and other potential 2024 hopefuls in both the Democratic and Republican parties.

For all the latest headlines, follow our Google News channel online or via the app.

Joe Biden

Biden, 80, has been teasing his plans to seek a second term for months but held off making an official announcement until Tuesday, four years to the day after he declared his 2020 candidacy. The 80-year-old Democrat, already the oldest US president ever, released a slickly produced video in which he declared it his job to defend American democracy. It opens with imagery from the Jan. 6, 2021, attack on the US Capitol by supporters of Trump. He does not face a serious threat from a Democratic challenger.

Donald Trump

Trump, 76, announced his election campaign last November as he faced some of the loudest criticism yet from within his Republican Party over his support for far-right candidates who were defeated in the midterm elections. Like Biden, he remains unpopular with great swaths of the electorate. But he has retained an firm grip on his base and strengthened his standing in polls after he was indicted by New York prosecutors in connection with an alleged hush money payment to a porn star. Trump is the frontrunner in the Republican race.

Ron Desantis

The Florida governor, who has styled himself as Trump but without the drama that surrounds the former president, has yet to announce but has made all the traditional moves of a would-be presidential candidate. DeSantis, 44, who ranks second to Trump in most polls, has signed bills imposing new restrictions on abortion and further loosening gun laws, positions that may help him in the Republican primaries but would likely hurt him among independent and more moderate voters in the general election. His battle with Walt Disney Co over its Florida theme park has unnerved some donors, as has his mixed messaging on continued US support for Ukraine and reluctance to respond aggressively to Trump’s personal attacks.

Nikki Haley

A former governor of South Carolina and Trump’s ambassador to the United Nations, Haley, 51, has emphasized her relative youth compared to Biden and Trump as well as her background as the daughter of two Indian immigrants. Haley has gained a reputation in the Republican Party as a solid conservative who has the ability to address issues of gender and race in a more credible fashion than many of her peers. She has also pitched herself as a stalwart defender of American interests abroad. She attracts about 3 percent support among Republican voters.

Tim Scott

The only Black Republican US senator has low name recognition outside his home state of South Carolina, but his optimism and focus on unifying his divided party have helped him draw a contrast with the more aggressive approach by Trump and DeSantis. Scott supporters, however, acknowledge that while his sunny demeanor is a selling point it may not be enough to defeat the front-runners, especially DeSantis, who can point to a list of conservative legislative accomplishments. Scott, 57, has launched a presidential exploratory committee but not yet confirmed he plans to run.

Asa Hutchinson

The former Arkansas governor launched his bid for the White House in April with a call for Trump to step aside to deal with his indictment. Hutchinson, 72, has touted his experience leading the deeply conservative state as proof he can deliver on policies Republican voters care about, citing tax cuts and job creation initiatives as particular sources of pride. Still, his name recognition remains limited outside Arkansas.

Mike Pence

Trump’s vice president has broken with his former boss over the 2021 attack by Trump supporters on the US Capitol, while Pence was inside the building. Pence, 63, says “history will hold Trump accountable” for his role in the attack. However, Pence, like other Republican White House hopefuls, came to Trump’s defense after New York prosecutors charged him in the hush money case, underscoring the fear of alienating Trump’s supporters in the primaries. Pence has said he is still deciding whether to seek the Republican nomination.

Chris Christie

The pugnacious former New Jersey governor is reported to be mulling a possible campaign. Christie, 60, who ran for president in 2016, is a one-time supporter of Trump, but turned against him over the 2021 attack on the US Capitol.

Chris Sununu

The New Hampshire governor is also testing the waters of a presidential run. Sununu, 48, who has served as governor of the small New England state since 2017, says the Republican Party needs new leadership and he does not believe Trump will be able to beat Biden.

Vivek Ramaswamy

A former biotechnology investor and executive, Ramaswamy, 37, launched a firm in 2022 to pressure companies to abandon environmental, social and corporate governance (ESG) initiatives. He announced in February he was running for the Republican nomination. The political outsider has excited a lot of grassroots chatter as a potential alternative to Trump but he remains a longshot candidate.

Robert Kennedy Jr.

An anti-vaccine activist, Kennedy, 69, is making a longshot bid to challenge Biden for the Democratic nomination. He is the son of US Senator Robert F. Kennedy, who was assassinated in 1968 during his own presidential bid. Kennedy has been banned from YouTube and Instagram for spreading misinformation about vaccines and the COVID-19 pandemic.

Mike Pompeo

Trump’s former secretary of state and director of the Central Intelligence Agency was seen as a potential contender, but he has decided not to run for personal reasons. The former Kansas congressman was one of Trump’s most loyal lieutenants and initially backed his false claims of a stolen presidential election in 2020.

Glenn Youngkin

The hedge fund manager turned Virginia governor was also seen as a possible contender for the Republican nomination after he focused on parents’ rights in schools in his gubernatorial campaign. Several of his key staff, though, have recently joined the DeSantis camp, however, suggesting that Youngkin, is not going to run in 2024.

Marianne Williamson

The best-selling author and self-help guru has launched her second, long shot bid for the White House. She ran as a Democrat in the 2020 presidential primary but dropped out of the race before any votes had been cast. She launched her latest campaign on March 23, saying she wants to challenge Biden in the Democratic nominating race.

Read more: New wave of GOP candidates to challenge Donald Trump, Ron DeSantis