Joe Biden braced for attacks from the Left as Democrat 2020 hopefuls debate for the first time

Joe Biden is braced for an onslaught of attacks from Left as Democratic presidential contenders attempt to pin back the front-runner in the first debates of the race, which begin on Wednesday.

Pollsters and party insiders have predicted that the former US vice president will be repeatedly targeted by his rivals in an attempt to close the substantial lead he enjoys in the opinion polls.

Mr Biden, who is running on a more centrist ticket than many in the field, has already seen his past stances on abortion, crime, climate change and working with political rivals criticised.

One senior Democrat congressional source told The Telegraph that “ganging up” on Mr Biden was likely, while a leading pollster predicted that other hopefuls would be "shooting" for him.

The first debates in the battle to win the Democratic Party’s presidential nomination, and with it the right to take on Donald Trump at the November 2020 election, begin on Wednesday.

Twenty candidates have made the cut, based on a combination of donation figures and polling. Ten will appear on stage together on Wednesday night and then another 10 on Thursday night.

The debates will take place in Miami, Florida - a key swing state in the presidential race which Mr Trump won in 2016.

It is a key moment in the long road to the 2020 election, marking the first time that Democrat candidates will square off against each other face-to-face after months of individual campaigning.

Mr Biden, who served for eight years as Barack Obama’s vice president, has consistently led in polls of Democratic candidates, often enjoying a double-digit lead over second-placed rivals.

However in a field with a number of prominent left-wing politicians, most notably Bernie Sanders who defines himself as a democratic socialist, Mr Biden risks being framed as a continuity rather than change candidate.

Larry Sabato, director of the Center for Politics at the University of Virginia, said Mr Biden's front-runner stance gave an incentive to the other politicians to focus their attacks on him during the debates.

“Essentially he’s going to have 19 other candidates shooting at his direction. The real question is whether it is withering fire or just the occasional potshot,” Mr Sabuto said.

He cautioned that Mr Biden’s candidacy may not be as strong as his poll-lead suggests given that he is universally known to voters, unlike his rivals, and yet still around two in three prefer another candidate.

A senior Democrat congressional source said that there would be “ganging up” on Mr Biden but warned that the strategy had risks given how little time each candidate will get to speak.

“I do think the attacks on Biden will become more frequent. But candidates run the risk of using all their time up attacking Biden," the source said.

“That wouldn’t be smart. The best path is to make sure the audience knows what you are about rather than coming off as a junkyard dog.”