US election 2020: Joe Biden boosted on Super Tuesday.

WASHINGTON -- US Democratic presidential candidate Joe Biden has picked up three endorsements from former rivals on the eve of the most important day in the 2020 White House race so far. Amy Klobuchar, Pete Buttigieg and Beto O'Rourke all campaigned with the former US vice-president in Dallas, Texas. On Super Tuesday, voters in 14 states will pick their preferred Democratic candidate for November's election. The Democratic frontrunner remains the left-wing senator, Bernie Sanders. Democratic moderates have been calling on party figures to urgently unite to stop Vermont Senator Bernie Sanders, a self-described democratic socialist, from becoming the party's nominee to take on President Donald Trump, a Republican. The other candidates still in the race are Elizabeth Warren, Michael Bloomberg and Tulsi Gabbard.

With the exception of Ms Gabbard, a Hawaii congresswoman, all of the Democratic hopefuls are...