The Democratic presidential contenders debated Tuesday in South Carolina in the final faceoff before both that state's primary Saturday and Super Tuesday in one week, as Sen. Bernie Sanders of Vermont emerges as the clear front-runner at this early stage in the 2020 nominating contest. 

Below, some winners and losers.

- - -

Winners

- Sen. Elizabeth Warren of Massachusetts: When it comes to debate performances spanning the last two weeks, Warren has been the strongest. She built a case for being a general-election candidate against President Donald Trump last week by taking the bark off former New York City Mayor Mike Bloomberg. And she followed it up with a studied and detailed performance on Tuesday. She picked up where she left off on Bloomberg by pointing to his past support for Republicans including South Carolina Sen. Lindsey Graham, a Republican, and also for the senator she beat in 2012, former Sen. Scott Brown, R-Mass. She also again argued that Bloomberg hadn't sufficiently addressed treatment of women at his company and went after him for doing business in China.

She was perhaps less forceful with Sanders, instead saying she would be a better president and going after his supporters. "I dug in. I did the work. And then Bernie's team trashed me for it," she said. "We need a president who is going to dig in, do the hard work, and actually get it done." You wonder if she really did much to help herself - especially given last week's debate didn't seem to do much for her - but she will at least remain on voters' radars after the last couple weeks.

- Former Vice President Joe Biden: He has regularly been a loser on this list, and he was again somewhat uneven on Tuesday night. But he's the leading candidate in South Carolina and is a player on Super Tuesday, and he seemed likely to continue to be after the debate. He also had some good moments, including in his appeals to black voters, which will be key on Saturday and Super Tuesday. He noted his work to secure funding for Charleston's port, and he talked about gentrification in a way we haven't heard much in this nominating contest thus far. Biden detracted from his performance somewhat by - again - repeatedly complaining about not getting enough time and blaming his Catholic upbringing for his obedience to rules about the length of answers. One thing to keep an eye on, though: When asked whether he'll press on if he doesn't win South Carolina, he said he'd win. He had better, at this point.

- Bloomberg's transparency about his money: There is kind of an unspoken bargain at play with Mike Bloomberg. It goes something like this: I may have only become a Democrat in 2018, and I may not be your ideal, but I can win - and oh, by the way, I have hundreds of millions of dollars from my own pockets to spend. Well, on Tuesday, that bargain came closer to being spoken. Early on, Bloomberg pitched himself by saying, "I have the experience, I have the resources, and I have the record." Later, he noted that he spent $100 million trying to elect House Democrats in 2018, but he momentarily seemed to almost say he "bought" something with that money.

- - -

Losers

- Sanders: After the candidates spent much of last week's debate focused on Bloomberg even though Sanders is threatening to take over the race, Tuesday night represented a course correction. Warren attacked Sanders for being ineffective. Former South Bend, Ind., Mayor Pete Buttigieg said Russia is helping Sanders, according to U.S. intelligence, because he serves its purposes. "Russia wants chaos, and chaos is what's coming our way," he said. "Imagine spending the better part of 2020 with Bernie Sanders against Donald Trump." Billionaire businessman Tom Steyer warned about having the government "take over the private sector." Biden mentioned the mass shooting in a black Charleston church in 2015 and noted that Sanders voted against the Brady gun control bill five times, which prompted Sanders to acknowledge it was a mistake. Biden and Buttigieg later on ganged up on Sanders for over the decades citing good things that authoritarian socialist regimes had done. It all prompted Sanders to say early on, "I'm hearing my name mentioned a little bit; I wonder why." Indeed. The question is whether it's too little, too late by his opponents.

- Bloomberg: It wasn't much better than last week, which was not very good. Bloomberg did little to make an affirmative case for himself, even on the electability front. And he offered mealy-mouthed rebuttals to some of the attacks on him, including by again downplaying women who complained about their treatment at his companies. Bloomberg said he was "probably wrong to make the jokes" but added "I don't remember what they were." He called it a "comment or two." And when Warren pressed him, he said, "The trouble is with the senator, enough is never enough. ... We did what she asked and thank you the world is probably better because of it." Bloomberg has released three women from nondisclosure agreements and said his company wouldn't use them going forward, but as Warren noted, he hasn't released all of them.

- The moderators: Two big problems here. One was that this was a complete free-for-all for much of the debate, with candidates talking over one another and no one enforcing the rules. Playing loose can work when it means the candidates actually debate, but many times Tuesday night, they were just allowed to talk past the moderators and game the system.

And second - and speaking of gaming the system - was that the booing and cheering were out of control. There is a reason many debates prohibit outward shows of support or dissent: Because it encourages people to stock the room and play to the cameras. We don't yet know if that's what happened Tuesday, but Bloomberg's supporters were especially vocal, and Sanders found himself booed a surprising amount, given he's competing for a South Carolina win.