Transcript for Bernie Sanders targeted in final debate ahead of South Carolina vote
We move on to last night's showdown. The democratic debate was a free for all with Bernie Sanders taking heat. Michael Bloomberg too as Joe Biden staked his claim to the state. Mary Bruce was in Charleston for all of the action. Good morning, Mary. Reporter: Good morning, George. Well, this debate last night was the last best chance for the candidates to try and take each other on before the critical primary here on Saturday. And before the race goes national next Tuesday and you could sense the desperation on the stage last night. It was chaotic and feisty, the candidates taking every chance they could to try and stunt Bernie Sanders' momentum. Overnight the candidates piing on the front-runner. Bernie, in fact, hasn't passed much of anything. I do not think that this is the best person to lead the ticket. Progressives have got one shot and we need to spend it with a leader who will get something done. I'm hearing my name mentioned a little bit tonight. I wonder why. Reporter: In a messy and combative fight his rivals pounced on his policies but Bernie Sanders stood firm behind his agenda. Do we think health care for all, Pete, is some kind of radical communist idea? Do we think raising the minimum wage to a living wage, the truth is -- One at a time. The American people -- that is why I am beating trump in virtually every poll and why -- Reporter: Eager to stunt Sanders' momentum Joe Biden with a bold declaration of about Saturday's must win primary. I intend to win south Carolina and I will inthe African friend vote here in South Carolina. Reporter: Biden took on Sanders' record on gun reform. If I'm elected, I'm coming for you and gun manufacturers, I will take you on and beat you. I'm the only one who's done it. Reporter: The senator forced to defend himself. Because of all of these disgusting and horrific mass shootings the American people now understand that we must be aggressive on gun safety, not be dictated to by the NRA. Reporter: Biden ripped into Sanders for his recent praise of Cuban dictator Fidel Castro in his literacy program. This man said he thought it was -- he did not condemn what they did. That is untrue categorically untrue. Authoritarianism of any stripe is bad. Period. But that is different than saying that governments occasionally do things that are good. Oh, come on. Reporter: Pete buttigieg with a warning. I am not looking forward tore a scenario with Donald Trump and his no taggic order for the 1950s and Bernie Sanders with one for the 1960s. Reporter: Michael Bloomberg tried to make light of his bruising first debate. I'm surprised he show up because I would have thought after I did such a good job beating them last week they'd be a little afraid to do that. Reporter: But he was still a top target. I don't care how much money mayor Bloomberg has, the core of the democratic party will never trust him. Reporter: In a blistering attack, Elizabeth Warren described being tried from her teaching job when she became pregnant at 21 and compared it to Bloomberg allegedly encouraging a pregnant employee to get an abortion. I packed up my stuff and I went home. At least I didn't have a boss who said to me, kill it the way that mayor Bloomberg -- I never said that. Was alleged to have said to one of his pregnant employees. Reporter: Bloomberg adamantly denies the allegation. I never said it, period, end of story. Categorically never said it. Reporter: Bloomberg argued he's best positioned to help the party succeed but raised eyebrows when he appeared to say he bought the democratic majority. All of the new Democrats that came in and put Nancy Pelosi in charge and gave the congress the ability to control this president I bought -- I got them. Reporter: He quickly corrected himself but the slip doing nothing to quell critics who say he's trying to buy the race. Mayor Bloomberg has a solid and strong and enthusiastic base of support. The problem is they're all billionaires. Reporter: Now, Joe Biden is expected to get a big boost here this morning. Sources tell us that congressman Jim Clyburn is poised to endorse him. The leading democratic voice here and as close as it gets to a kingmaker in this state. Thanks very much. Let's get more from Jon Karl and it was as I said earlier just a real free for all. You could see the focus on Bernie Sanders and all the opponents up there on the stage basically know if he wins on Saturday in South Carolina, he's on a solid path to the nomination. Reporter: No question about it, George. You could see the other candidates acting as if they were running out of time. This was a chaotic, loud, bruising debate. Sanders came under fire in a way he has never come under fire before and for the first time he actually seemed a little rattled, especially when the crowd started booing but at the same time, George, it was such a free for all that nobody on that stage really stood out as the primary alternative to Bernie Sanders and it may actually have been in a way a good night for him because Elizabeth Warren once again did him a favor by relentlessly going after Michael Bloomberg. Now it's up to the voters in South Carolina on Saturday. We did hear for the first time in one of these debates coronavirus discussed. The president's been putting a lot of focus on that tweeting all the way back on his plane from India. Reporter: Yeah, first of all, it was odd it didn't come up until the debate was almost over. When it did, the Democrats were actually united on this one, criticizing Donald Trump for among other things proposing cuts to the funding of the CDC. The president tweeted the CDC and my administration are doing a great job of handling coronavirus. That obviously is a statement that at the very best is premature. Next Tuesday night, 16 contest, essentially a national primary. Special coverage at ABC. I'll anchor with our political team starting at 8:00 eastern.
This transcript has been automatically generated and may not be 100% accurate.