Ex-US vice president Joe Biden launches White House bid

Former US Vice President Joe Biden has formally launched his presidential election campaign, placing himself as the frontrunner among Democratic Party candidates seeking to challenge President Donald Trump in 2020.  

Biden announced the third presidential bid of his career by social media on Thursday, declaring the "soul of this nation" is at stake if Trump wins re-election.

"We are in the battle for the soul of this nation," Biden said. "If we give Donald Trump eight years in the White House, he will forever and fundamentally alter the character of this nation — who we are. And I cannot stand by and watch that happen."

The 76-year-old Biden becomes an instant front-runner alongside Vermont Senator Bernie Sanders, who is leading many polls and has proved to be a successful fundraiser.

Biden gained "some genuine goodwill" with voters over his career, over 36 years as a senator and then eight years as former President Barack Obama's deputy, Kyle Kondik of the University of Virginia's Center for Politics told AFP.

However, Biden must compete in a field that now spans at least 20 Democrats with a diverse and relatively young background. As an older white man with occasionally centrist views, Biden has to prove he's not an outlier in his party.

Biden’s critics in both major political parties were quick to attack him.

"The old guard of the Democratic Party failed to stop Trump, and they can't be counted on to lead the fight against his divide-and-conquer politics today," the liberal group Justice Democrats tweeted. "The party needs new leadership with a bold vision capable of energizing voters in the Democratic base who stayed home in 2016."

Complicating matters, Biden has been struggling with a recent scandal after multiple women accused him of touching them inappropriately or making them feel uncomfortable with his affection.

Moreover, the recent controversy over his tactile style, particularly with women, could dampen his campaign.

Biden has a reputation for awkwardly touching the wives, mothers or daughters of senators during swearing-in ceremonies, and he came under criticism for massaging the shoulders of then defense secretary Ash Carter's wife in 2015.