COLUMBIA, S.C. – Former vice president Joe Biden decisively won the South Carolina primary Saturday, as the first Southern primary contest reshaped the race and dealt a blow to the surging candidacy of Sen. Bernie Sanders.

The win pumped new life into Biden’s struggling campaign, as he became the first candidate to score a clear-cut victory against Sanders this year, boosting his efforts to become the major alternative to the liberal senator. Still, Sanders, I-Vt., is polling strongly in several of the Super Tuesday states that vote this week, and it could yet prove difficult for any of his competitors to catch up.

At a minimum, Democrats now face the most unsettled contest in decades, with several candidates showing a potential to win delegates after the winnowing process of the first four primary states. The Democratic race goes national Tuesday, when 14 states and one territory will vote to award 34 percent of the convention delegates.

What’s not clear is whether Biden’s triumph in a state supporters have long called his “firewall,” where African American voters had a significant say for the first time, will provide only a momentary lift, result in a two-person race between Biden and Sanders – or result in a long slog to the convention.

Still, it was a major win for a figure who has been in public life for 45 years, and his first primary victory in his three presidential runs. Cheers went up at 7 p.m. at a Biden election-night rally in Columbia when MSNBC called the race, and again at 7:04, when the channel was switched to CNN. Biden cast the win as the first of many number of dominoes that will now fall his way, noting that some were counting him out just days ago.

“Now, thanks to all of you – the heart of the Democratic Party – we just won and we won big . . . and we are very much alive,” Biden said in a victory speech that was pointed directly as Sanders.

“We have the option of winning big or losing big. That’s our choice,” Biden told a raucous crowd in Columbia. “We have to beat Donald Trump and the Republican Party, but here’s the deal: We can’t become like them. . . . We can’t have a never-ending war.”

The Biden campaign hopes to use Saturday’s win to consolidate support from many of his rivals, hoping that several drop out – which one of them, businessman Tom Steyer, did shortly after the polls closed. “Honestly, I can’t see a path where I can win the presidency,” Steyer said in announcing his decision.

Biden also plans a series of high-profile endorsements over the coming days. Rep. Robert “Bobby” Scott, D-Va., and former Virginia governor Terry McAuliffe announced shortly after Biden’s win that they were backing the former vice president.

Nearly half of South Carolina voters said Rep. James Clyburn’s, D-S.C., final-week endorsement of Biden was an important factor in their vote, according to exit poll results from Edison Research.

Sanders, speaking in Virginia Beach on Saturday night, sought to put the results in perspective, ticking off his previous strong performances in Iowa, New Hampshire and Nevada.

“But you cannot win ’em all . . . and tonight we did not win in South Carolina,” Sanders said. “And that will not be the only defeat. There are a lot of states in this country, and nobody wins them all.”

After congratulating Biden, he proclaimed, “And now we enter Super Tuesday – and Virginia!”

For all the candidates but Sanders, a further winnowing of the field is crucial to winning the nomination. Sanders is broadly expected to come out of Tuesday with a substantial delegate lead in the race, anchored in his huge polling advantage in California. Under party rules, such leads can be difficult to overcome as the race moves on.

With most precincts reporting, Biden was poised to win about half the vote, giving him a symbolic victory over Sanders, who did not win more than 34 percent of the vote in any of the first three states. Under party rules, nominees need to secure more than 50 percent of delegates to win the nomination at the convention in Milwaukee in July.

But the continued viability of so many candidates has increased the likelihood that no candidate will be able to secure such a victory with initial pledged delegates alone, setting up the potential for either a brokered convention or a pre-convention horse trading of delegates by the candidates.

Complicating the hunt for the nomination is former New York mayor Mike Bloomberg, who has spent hundreds of millions of dollars advertising his candidacy to the Super Tuesday states, after deciding not to compete in the first four contests.

Although his rise in polls had slowed since his first debate performance, Bloomberg still appears positioned to win delegates in many early states, as he continues to swamp his rivals in spending.

His advisers vowed Saturday night that Bloomberg will stay in the race at least through Super Tuesday, when he will appear on the ballot for the first time. They cited internal campaign data showing that if Bloomberg dropped out it would strengthen Sanders, whose left-leaning policies the former mayor abhors.

“Mike Bloomberg has not been on the ballot yet,” said Bloomberg campaign manager Kevin Sheekey. “Our campaign is focused on organizing Democrats and building infrastructure in states all around the country.”

His campaign announced Saturday that he will buy three minutes of commercial airtime nationally at 8:30 p.m. Sunday night to present his vision for managing the current coronavirus outbreak, which claimed its first American life this past week in Washington state.

After Saturday’s outcome became clear, President Donald Trump tweeted, “Sleepy Joe Biden’s victory in the South Carolina Democratic primary should be the end of Mini Mike Bloomberg’s Joke of a campaign.”

Biden’s support among black voters, who made up most of the electorate in South Carolina, appeared ready to lift a campaign that has struggled to find its footing for more than a year. Biden, a national polling leader in 2019, finished in fourth place in Iowa, fifth place in New Hampshire and second place in Nevada.

African American voters are a crucial pillar of the Democratic coalition, and Biden, along with other Sanders critics, have argued that it will be hard for the Democratic nominee to defeat Trump if he does not have enthusiastic support from the black community. Sanders has replied that he alone among the Democratic contenders has shown the ability to electrify voters and draw big crowds from a broad portion of the electorate.

Before polls closed, Clyburn, who has promised to campaign for Biden in North Carolina next, voiced strong criticism of the operation he was joining.

“If we are successful tonight in this campaign, if he has a relaunch,” he told CNN, “I think we will have to sit down and get serious about how we retool this campaign, how we retool the fundraising, how we do the [Get Out The Vote]. And at that point in time, many of us around the country will be able to join with him and help him get it right.”

Steyer had invested heavily in South Carolina, spending $23.6 million on advertising out of the $36 million spent by all of the candidates, according to the tracking firm Advertising Analytics. But the results showed he did not get a big return on his money.

Former South Bend, Indiana, mayor Pete Buttigieg, who came in first in Iowa and second in New Hampshire, left South Carolina long before voting results came in, a tacit admission of his campaign’s low expectations in the state.

His inability to build trust among black voters, despite his early momentum, proved damaging in the state, where he regularly appeared at events designed to appeal to black voters but failed to draw many attendees.

His campaign staff has shifted to a more target-specific strategy for Super Tuesday, advertising heavily in specific parts of the country, like the Sanders stronghold of Vermont and Norfolk, Virginia, to boost his delegate haul. The campaign, advisers say, is focused on getting to the 15 percent margin threshold required by party rules to win delegates in as many places as possible.

“I think there is going to be after Super Tuesday a real focus on narrowing the field,” Michael Halle, a strategist for the Buttigieg campaign, said in a call with reporters Saturday. “The candidate or candidates who are closest to the margin are going to be able to stay in.”

Sen. Elizabeth Warren, D-Mass., once seen as among the strongest candidates, had another disappointing showing, after finishing third in Iowa, fourth in New Hampshire and fourth in Nevada. But her campaign has been encouraged by a recent increase in fundraising following two solid debate performances, and she has been helped by an outside group spending millions of dollars in states that vote Tuesday to help her campaign.

Warren also won the endorsement Saturday of Randi Weingarten, president of the American Federation of Teachers. Weingarten was acting in her personal capacity – her union decided to support Biden and Sanders as well as Warren – but as a major figure in the labor and education worlds, her backing could carry weight.

The other player in the race is Sen. Amy Klobuchar, whose home state of Minnesota will vote Tuesday. She also has an aggressive travel schedule over the coming days and has been competing on television in several states, both from her campaign and a supportive outside group.

The South Carolina primary provided sharply different guidance for the party than the previous three contests. But the bigger role of black voters, along with broader concerns about Sanders’s effect on Democratic prospects in a general election, up and down the ballot, appeared to have given Biden a second chance.

“Look, I’m very optimistic about today, and I’m very optimistic about the process,” Biden told reporters at a polling place in Greenville earlier in the day.

He said his campaign had been bringing in “about a million dollars a day over the last week or so, and if we win solidly here I think it’s going to raise a lot of money as well.”

“The bigger the win, the bigger the bump,” he said.

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The Washington Post’s Chelsea Janes in Raleigh, North Carolina, contributed to this report.