Michael Bloomberg said Russia was working to help Sanders win the nomination
Democratic White House hopefuls rounded on leftist frontrunner Bernie Sanders at a feisty debate on Tuesday, attacking him as too extreme for American voters and a weak challenger to President Donald Trump.
Joe Biden, who needs a victory in South Carolina's crucial primary on Saturday to keep his campaign alive, hit Sanders as soft on gun control, while billionaire tycoon Michael Bloomberg said Russia was working to help Sanders win the nomination -- betting he will be defeated in November.
"Vladimir Putin thinks that Donald Trump should be president of the United States, and that's why Russia is helping you get elected so you'll lose to him," the former New York mayor told Sanders in a heated opening exchange.
"I'm the one choice that makes some sense," Bloomberg added.
Senator Elizabeth Warren, a fellow progressive, also attacked Sanders for not explaining how his costly programs like universal health care, a $15 minimum wage and tuition free college would be paid for.
"I dug in, I did the work," Warren said of her own plans to pay for similar programs, "and then Bernie's team trashed me for it."
Sanders, 78, had emerged largely unscathed from the last debate, but he acknowledged he was now in the firing line, with rivals seeking to derail his push for the nomination following two straight victories, in New Hampshire and then Nevada.
"I'm hearing my name mentioned a little bit tonight," he said to laughter. "I wonder why."
Sanders is in pole position heading into South Carolina's primary and the debate offers a late-hour opportunity for other Democratic hopefuls, former vice president Biden in particular, to halt his momentum.
The leftist senator from Vermont had finished in a virtual tie with former South Bend, Indiana mayor Pete Buttigieg in the first nominating contest, in Iowa.
Bloomberg seeks to rebound
South Carolina is the final early vote before the race takes on a national dynamic on "Super Tuesday" March 3, when 14 states vote and a whopping one third of all delegates -- the candidates' representatives who formally pick the nominee at the Democratic Party's July convention -- are up for grabs.
Seven candidates are taking part in the debate in Charleston, the 10th debate of the campaign cycle.
Also on stage were Senator Amy Klobuchar and billionaire activist Tom Steyer.
Bloomberg, 78, was seeking to rebound from a disastrous performance last week in his first debate and prove he is a credible, moderate alternative to the leftist Sanders.
The 77-year-old Biden has also been staking out the center and aims to bounce back from dismal showings in Iowa and New Hampshire, where he finished fourth and fifth respectively.
The former vice president came in second in Nevada's caucuses, but with 20.2%, he was well behind Sanders' 46.8%.
Biden has been counting on strong support among black voters in South Carolina to recharge his flagging campaign.
The state is the first contest featuring a substantial African-American electorate, a crucial voting block in the Democratic primary process.
A new Reuters Ipsos poll shows support for Biden slipping among black voters nationwide by 10 points in recent weeks, to 23%, while Sanders saw his support rise seven points to take the lead at 26%.
A Sanders victory in South Carolina, or even a close second, could set him up for a knockout blow on Super Tuesday.
Some Democrats argue that Sanders, who calls himself a "democratic socialist," is too far to the left for many Americans and would be a weak opponent against Trump in November.
That is a line of attack which the 38-year-old centrist Buttigieg employed in the last debate, when he called Sanders "polarizing."
Sanders clearly believes he is more in touch with the sentiments of Democratic voters than his rivals.
"Is guaranteeing health care to all people as a human right a radical idea? Is addressing the existential threat of climate change a radical idea?" Sanders asked attendees at a CNN town hall Monday in Charleston.
The questions were met with chants of "No" from the crowd, leading him to say, "I rest my case."