CHARLESTON, S.C. — Everyone knew that Bernie Sanders would be the principal target in Tuesday's Democratic debate. But the stop-Sanders movement, as represented by the six other candidates on the stage, sputtered and struggled to keep the focus on the candidate who leads the race for the party's nomination.

The tone of the debate ultimately became a metaphor for the Democratic race itself, as it was marred repeatedly by candidates interrupting one another, talking over each other and constantly ignoring the moderators’ efforts to bring some order to the unruly evening. The event did little to raise the confidence level of the Democratic voters who will be selecting a nominee to go up against President Trump.

What the evening highlighted was the degree to which Sanders stands apart from the field, with the other candidates divided and sparring with one another as much as with the senator from Vermont. Sanders has his base, and it has served him well enough so far. The others are trying to find theirs. None of Sanders’s rivals rose significantly above the others. For Sanders, that was probably a satisfactory outcome.

The tenth Democratic presidential debate in Charleston, S.C., was interjected with lots of crosstalk and a few zingers. (The Washington Post)

Sanders’s rivals landed blows throughout the debate, on issues litigated in past forums and on some newly raised, and Sanders’s performance was not his finest. He was on the defensive at many points during the evening, whether on the cost of his Medicare-for-all plan, his record on gun issues or, more recently, about his comments praising Fidel Castro’s Cuba and its literacy programs.

He took fire from former vice president Joe Biden, former South Bend, Ind., mayor Pete Buttigieg, Sen. Amy Klobuchar (D-Minn.), businessman Tom Steyer and former New York mayor Mike Bloomberg. He even took criticism from Sen. Elizabeth Warren (D-Mass.), who defended their shared progressive values and agendas but accused him of being a politician who doesn’t get things done.

Sanders acknowledged at least one mistake, a vote to exempt gun manufactures from being sued. “I have cast thousands of votes, including bad votes,” he said. “That was a bad vote.” But in almost every other exchange, he stood his ground. He repeatedly returned to his foundational message, the message he has sounded consistently since 2016.

Democratic presidential candidates sharpened their message inside the spin room following the Feb. 25 debate in Charleston, S.C. (The Washington Post)

What is different, he argued, is that ideas once described as on the fringes of the Democratic Party are now part of the mainstream of the Democratic Party. Some rivals disagree, but it is their task to attract enough support to prove Sanders wrong.

Whether the collective attacks on Sanders will blunt his momentum won’t be known immediately. But what’s even more difficult to assess is what might have happened if the other candidates had taken Sanders more seriously earlier and subjected him to sustained cross-examination over a period of months.

Sanders has escaped that kind of scrutiny, just as he managed to avoid a worse pummeling on Tuesday night, as his rivals had other battles to fight in their effort to demonstrate to Democratic voters that each should become the sole and singular alternative to Sanders.

That was supposed to be Biden. Instead, he faces a crossroads here Saturday. He long has marked the primary in South Carolina as the most critical test of his candidacy, and it has become all the more so as a result of his performances in the first three contests. Asked about slipping poll numbers and the future of his candidacy, Biden said defiantly, “I will win South Carolina.” He has now put down the marker that will define the rest of his candidacy.

But others face similar crossroads. Buttigieg and Klobuchar are not anticipating strong finishes in South Carolina, adding to the pressure on their candidacies. Warren, who was again the most aggressive candidate on the stage, has similar pressures on her. But while she nominally criticized Sanders, her main target for the second debate in a row was Bloomberg.

The former New York mayor rebounded somewhat from his poor performance in Las Vegas, sounding more composed and more vigorous in his rebuttals to Warren and others. But Warren sought to disqualify him in another way, arguing that his record of funding Republicans in past years should make him unwelcome to the Democratic Party of 2020.

“The core of the Democratic Party will never trust him,” she said. “He has not earned their trust.”

That is still a question facing the former mayor, and whether he did enough to erase the damage from last week is another. But he isn’t on the ballot here Saturday, having skipped the first four contests to concentrate on Super Tuesday next week.

Though the location of Tuesday’s debate may have been South Carolina, for all the candidates, this was as much an opportunity to appeal to the audience of voters who will cast ballots on Super Tuesday as it was to speak to Democrats in the Palmetto State.

With 14 states and two other jurisdictions holding contests next week, the Democratic race suddenly morphs into a nationalized contest where winning delegates becomes the most important priority. Among the biggest prizes are California and Texas, which together will award 643 delegates.

Roughly one-third of the pledged delegates at stake in the nominating contest will be selected on Tuesday. With the opposition to Sanders still fighting among themselves as much as with him, the coming contests provide Sanders an opportunity to amass enough delegates that he would be likely to go into the national convention in Milwaukee this summer as the leader, even if short of a majority.

Sanders has been the target of criticism at other debates, but no rival previously mounted the kind of sustained attack he underwent Tuesday from all the others on the stage. After he cruised through the first three contests — winning New Hampshire and Nevada and in a virtual tie with Buttigieg in Iowa — his rivals finally woke up in an effort to blunt his early momentum.

A week ago in Las Vegas, Sanders escaped serious scrutiny from the other candidates, though his position at the head of the pack was no less obvious than it was Tuesday night. He escaped because others were more interested in putting down Bloomberg, who was making his first appearance on the debate stage.

Sanders’s rivals succeeded in that mission, with considerable help from the mayor’s shaky performance. But with Bloomberg under attack throughout the debate, Sanders skated through the evening with only a scratch or two.

He got more than scratched Tuesday night, and at a moment or two, he seemed temporarily hesitant, particularly on the issue of guns. But those moments generally passed quickly as the shouting and the interruptions overwhelmed the stage.

Biden, inexplicably, was the lone candidate who often held back, questioning his own judgment repeatedly as others plowed ahead past their allotted times and the moderators’ pleadings for them to stop talking.

For Trump, this was one more debate that served his purposes. A divided Democratic Party and a nomination battle that often seems to do as much to diminish the candidates as to elevate them is what he enjoys seeing.

Only rarely did the candidates make a case against the president, particularly the president who since impeachment has been wielding his power against whoever he deems disloyal or hostile. Only rarely did they raise their visions and speak more affirmatively to the electorate that will decide the outcome in November.

For now, they are focused on one another, for all the obvious reasons. There is a nomination to be won, and right now, Sanders has an advantage. The debate did little to change that trajectory, and it will be left to the voters to sort things out.