Former US vice president and Democratic elder statesman Joe Biden launched his third White House bid Thursday, becoming the frontrunner in a crowded field and painting incumbent Donald Trump as a "threat" to America.
The 76-year-old is the most experienced and best recognized Democrat in the running, a veteran campaigner who has dominated early polls following months -- even years -- of planning.
In a campaign launch video, Biden said he couldn't stand by and watch Trump "fundamentally alter the character of this nation" during a second four-year term.
Biden criticized the president's response to a deadly 2017 white supremacist rally in Charlottesville, Virginia, recalling that Trump infamously described "very fine people" on both sides of the clashes.
"And in that moment I knew the threat to this nation was unlike any I had ever seen in my lifetime," Biden said.
The Democratic stalwart, for eight years Barack Obama's deputy, added that he couldn't remain idle while Trump stood to gut America's core values and "everything that made America America."
Trump's response was swift: he insulted Biden on Twitter, his favorite forum for smacking down rivals, casting doubt on his opponent's mental capacity.
"Welcome to the race Sleepy Joe. I only hope you have the intelligence, long in doubt, to wage a successful primary campaign," Trump tweeted.
He returned to the theme later on Fox News, telling host Sean Hannity that Biden "is not the brightest light bulb in the group" but "he has a name that they know."
Biden has managed to keep his working-class appeal intact despite nearly half a century in Washington politics.
He is seen as a comforting, known quantity for American voters who will be vetting 20 Democrats now officially in the race.
Hours after his announcement, the gregarious Biden was in his element, pressing flesh and posing for photographs at a Wilmington, Delaware pizza parlor.
"Who's the best person to lead the country? That's what this is going to be all about and it's going to be for the voters to decide that," he told reporters.
Even before his official launch, Biden led most surveys of Democratic voters. But recent controversy over his tactile style, particularly with women, could dampen his rollout.
The RealClearPolitics poll aggregate puts him as favorite with 29.3 percent support, followed by independent Senator Bernie Sanders, who votes with the Democrats, at 23 percent.
Both white men in their 70s, the two are unlikely to be seen as the ideal shop window for a party seeking to win over young and minority voters.
Biden finds himself in a field of unprecedented diversity -- six contenders are women and three are black -- as he makes his third presidential run, following unsuccessful attempts in 1988 and 2008.
After the death of his son Beau from cancer, Biden opted out of a presidential campaign in 2016.
Speaking on Fox, Trump opined that unlike Biden, Sanders "has a lot of energy," but it was "misguided" and he had done poorly as a legislator.
He similarly dismissed Texan Democrat Beto O'Rourke as "fading very fast," and said Senator Kamala Harris "has got a little bit of a nasty wit but that might be it."
Pete Buttigieg, the 37-year-old Midwestern mayor whose insurgent candidacy has caught observers by surprise "is not going to make it (though) I would hope he would," Trump added.
Complicating matters for Biden, the last weeks have been clouded by accusations from multiple women who say he touched them inappropriately or made them feel uncomfortable with his shows of affection.
Biden, an old-school politico who acknowledges he is quick to offer hugs and shoulder rubs, has not outright apologized, but pledged to be "more mindful" about society's changing boundaries.
In another apparent attempt to defuse a key vulnerability for the Democratic candidate, Biden earlier this month called Anita Hill -- the woman at the center of emblematic sex harassment hearings three decades ago -- to express "regret for what she endured" during her testimony.
Hill, a law professor, confirmed the call to The New York Times but also said Biden stopped short of an apology, saying she was not convinced he accepts the harm she says he caused her and other harassment victims.
Obama, through a source close to his thinking, praised Biden but pointedly avoided endorsing, preferring to "let the candidates make their cases directly to the voters."
Biden concurred, saying he had discouraged his former boss from any public blessing because "whoever wins this nomination should win it on its own merits."
Biden enters the race months after rivals, and trails in a key benchmark: fundraising. He headed Thursday to Philadelphia, reportedly to attend a high-dollar fundraiser hosted by a telecoms executive. On Monday he travels to Pittsburgh, another city in must-win Pennsylvania, for his first major campaign event, a labor union address.
Washington, United States | AFP