CHARLESTON, S.C. -- One night after a dinner noted for its decorum and Southern civility, the 2020 Democratic presidential candidates eagerly savaged one another, seeking advantage just four days before the pivotal South Carolina primary.

All of the candidates on the debate stage Tuesday night hold positions at least as progressive as the last Democratic president’s. The overarching narrative, then, tumbled into arguments about electability and effectiveness.

CBS moderators asked Bernie Sanders, the current front-runner, how he planned to pay for $50 trillion in proposed new spending, including an estimated $30 trillion for “Medicare for All.” Could he do the math on stage?

“How many hours do you have?” he shot back.

“That’s the problem,” Joe Biden interrupted.

Annoyed by the former vice president’s snarky aside, the self-described democratic socialist asserted that people’s overall health care outlays would go down as government spending goes up. “What we need to do,” Sanders said, “is to do what every other major country on Earth does: guarantee health care to all people, not have thousands of separate insurance plans."

He barely got this answer out before Amy Klobuchar interrupted. Not only would his spending dwarf the American economy, the Minnesota senator complained, Sanders was out of step with what voters want. All of it, she continued, would amount to “a bunch of broken promises that sound good on bumper stickers.”

Sanders tried shouting a rebuttal as Pete Buttigieg started talking over him. When the moderators finally quieted the cross-talk, the former South Bend, Ind., mayor had calculated the political cost to Democrats: “It adds up to four more years of Donald Trump, Kevin McCarthy as speaker of the House, and the inability to get the Senate into Democratic hands.”

Sanders was hardly the innocent victim of this sort of exchange. He got the first question: How could he convince voters to turn away from President Trump when the economy is doing so well? The Vermont senator turned his answer into an attack on the former mayor of New York, a deep-pocketed latecomer to the race: “Well, you're right. The economy is doing really great for people like Mr. Bloomberg and other billionaires.”

Bloomberg responded in kind, saying Russian President Vladimir Putin wants Trump to remain in the White House, which is “why Russia is helping you get elected, so you will lose to him.”

It was a reference to unsubstantiated reports that Russia is backing the new front-runner with a disinformation campaign, and Sanders countered by citing Bloomberg’s past praise of the leader of communist China: “I'm not a good friend of President Xi of China. I think President Xi is an authoritarian leader.”

The dueling references to foreign tyrants was unusual at a debate that was supposed to focus on kitchen table issues. Biden holds an eight-percentage-point lead in South Carolina and has long insisted that he would succeed in a more diverse state that better reflects the makeup of the country. But he was left sputtering as moderators failed to stifle all the shouting.

“I guess the only way to do this is to jump in and speak twice as long as you should,” he said with exasperation when other candidates kept talking over the allotted 90-second limit.

“I know you cut me off all the time, but I’m not going to be quiet anymore, OK?” he complained when a moderator tried to cut another answer short. "Why am I stopping? No one else stops," he later sighed.

Biden has the most to lose in South Carolina after finishing fourth in Iowa, fifth in New Hampshire and second in Nevada. He has built a last-ditch firewall in the Southern state. To preserve it, he invoked the name of his old boss to attack Sanders, noting how Sanders had mulled a 2012 primary challenge against Barack Obama. Being a true progressive doesn’t mean passing purity tests, he said. “Progressive is getting things done,” Biden argued, “and that's what we got done. We got a lot done.”

Critiques such as this one weren’t uttered only by moderates. Elizabeth Warren and Sanders share a similar policy portfolio, she noted, “but I think I would make a better president than Bernie” because “getting a progressive agenda enacted is going to be really hard, and it's going to take someone who digs into the details to make it happen.”

No one accused Bloomberg of not getting things done. It was what the former mayor has done that drew his competitors’ criticism. They accused him of enforcing racist stop-and-frisk policies as mayor and of forcing female former employees to sign non-disclosure agreements in settling complaints about inappropriate comments he allegedly made.

When Warren leveled that last charge, the billionaire objected. He had already released three women from those contracts, and besides she was just “relitigating” an old issue. At this, Buttigieg jumped in: “And if you get nominated, we'll be re-litigating this all year.”

The barbs and counter-barbs and counter-counter-barbs went on and on. Should Sanders become the nominee, Trump will use the standard-bearer’s far-left ideology as a cudgel against him, billionaire philanthropist Tom Steyer said. He previewed the president’s attack, starting politely enough by  praising the front-runner for identifying many of the problems facing the country. “The difference is,” Steyer continued, “I don't like his solutions. I don't believe that a government takeover of large parts of the economy makes any sense for working people or for families.”

This criticism was tamely expressed compared to the attacks Sanders received over his recent comments about Cuba, in particular his praise of Fidel Castro’s “literacy programs.” Yes, Sanders replied, he had trumpeted such social initiatives advanced by the late dictator. No, the senator continued, he had not endorsed the authoritarianism that accompanied them. But again, this was too much for Buttigieg: Democrats would fail, he said, if they must champion a nominee who encouraged the public to “look at the bright side of the Castro regime.”

“I’m not looking forward to a scenario where it comes down to Trump, with nostalgia for the social order of the 1950s, and Sanders, with nostalgia for the revolutionary politics of the 1960s,” he continued.

There were other arguments, most of them accompanied by raised voices. It was a noisy and final debate before the last dance ahead of not just the Palmetto State’s primary but Super Tuesday. Some were surprised by the tumult, including Steyer, who told RealClearPolitics that “the debate got a little away from the moderators from time to time, for sure.” Others were more than disappointed, including a senior South Carolina Democratic official.

“The staff of these candidates are performing political malpractice,” the official said on condition of anonymity. “This was an opportunity to connect with the folks of South Carolina — to share the stories and heartaches, the dreams and pains of the people they have met over the past year.”

“They all failed miserably,” the official concluded. South Carolina votes on Saturday.