Joe Biden drops out of 2024 election race, endorses Kamala Harris

US President Joe Biden (L) and US Vice President Kamala Harris hold hands and gesture as they watch the Independence Day fireworks display from the Truman Balcony of the White House in Washington, DC, on July 4, 2024. [AFP]

Joe Biden on Sunday dropped out of the US presidential election and endorsed Vice President Kamala Harris as the Democratic Party's new nominee, in a stunning move that upends the 2024 race for the White House.

The 81-year-old Biden stepped aside after weeks of pressure from Democrats following a disastrous debate performance, throwing the election battle against Republican Donald Trump into unprecedented turmoil.

"While it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and focus solely on fulfilling my duties as President for the remainder of my term," Biden said in a letter on X while recovering from Covid at his beach house in Delaware.

Biden said he would "speak to the nation later this week in more detail about my decision."

He later added that he was backing Harris -- who is the first female, Black and South Asian vice president in US history, and will now be aiming to become its first female commander-in-chief.

"Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year," Biden said on X. "Democrats — it’s time to come together and beat Trump. Let’s do this."

Biden is the first president in US history to pull out so late in an election race, and the first to bow out because of concerns over his mental acuity and health.

Trump quickly reacted, saying Biden had not been "fit to run" or "fit to serve" as president.

Biden spent more than three weeks resisting calls to step down following the shock of the June 27 debate, at one point insisting that only the "Lord Almighty" could convince him to back out.

In a bid to show he was up to the job, he gave a number of interviews and what was billed as a "big boy" press conference in which he took numerous questions, but made further gaffes including calling Harris "Vice President Trump."

A tide of voices within his own party calling on him to go, starting with donor and actor George Clooney and ending with former president Barack Obama, sealed his fate.

Chaotic period for US

The end finally came shortly after Biden had been diagnosed with Covid, forcing him off the campaign trail and into isolation in Rehoboth Beach.

Biden's decision to pull out also caps a tense and chaotic period in the US election, with Trump having survived an assassination attempt at a campaign rally on July 13.

Biden joins a small club of US presidents who have decided to throw in the towel after just one term, with the last being Lyndon Johnson in 1968 -- a year also marked by political turmoil and violence.

Johnson's replacement as nominee, then-vice president Hubert Humphrey, went on to lose heavily to Richard Nixon.

But Democrats are counting on Harris to fare better, and hoping that she can prevent convicted felon Trump from making a sensational comeback to the Oval Office.

In recent weeks, the Biden campaign has reportedly been quietly carrying out a head-to-head survey of voters measuring how she matched up against Trump.

While Harris struggled to make an impact in her first years in the White House, she has emerged in the last year as a strong performer on the campaign trail on key messages such as abortion rights.

The former prosecutor has also made much of her life story as the first woman in US history to hold the vice presidency, as well as the first person of Black and South Asian origin.

Barring opposition from her party, Harris is now set to be nominated at the Democratic National Convention in Chicago on August 19 in what promises to be a dramatic moment -- and a heartrending one for Biden.

Biden took office in January 2021 pledging to heal the "soul of America" after four turbulent years under Trump and the shock of the January 6, 2021 Capitol assault by his supporters.

Overcoming a reputation for verbal flubs, Obama's former vice president pushed through a massive Covid recovery plan and a green industry scheme.

US allies welcomed his pledge that "America is back" following Trump's trampling on international alliances, and his strong support for Ukraine as it battled Russia's 2022 invasion.

But he faced criticism over the catastrophic US withdrawal from Afghanistan and inflation that meant overstretched Americans ignored otherwise positive economic numbers.

Behind it all were the ongoing concerns about his age with a series of senior moments, including tripping up the stairs to Air Force One and falling off his bike, contributing to the doddery image played up by Republicans.