South Carolina Gives Hillary Clinton Her Most Important Win Yet

COLUMBIA, South Carolina — Hillary Clinton dealt Bernie Sanders a bruising defeat in South Carolina's Democratic primary Saturday, with early returns showing her crushing the insurgent senator by a 3-to-1 margin.

While the win was no surprise, it was still one of the best nights of Clinton's second attempt at the presidency thus far because it proved the basic electoral theory of her campaign: That a strong advantage among minority voters would carry her to her party's nomination — and potentially all the way to the White House.

The resounding victory makes it clear that Sanders, despite his best efforts, has been unable to address his fundamental weakness with black voters.

Sanders on South Carolina Defeat: 'We Got Decimated' 2:40

African Americans represented 61 percent of the turnout in the sate's Democratic presidential primary — up from 57 percent in 2008 — and Sanders lost the group 84 percent to 16 percent, according to NBC News exit polls.

If Sanders couldn't close the gap among African Americans in South Carolina, where he had the most time, money, and resources devoted to introducing himself to the community, then it will be all the more difficult in upcoming states.

Sanders made a real effort to compete here, hiring more than 200 paid canvassers and visiting the state on numerous occasions.

Clinton: Let's Make America Whole Again 1:42

But for African Americans, who have known and liked the Clinton family for more than 25 years, Sanders' effort was too little, too late — or perhaps doomed from the start.

Rep. Jim Clyburn, the state's top Democrat whose late endorsement for Clinton gave her an extra boost, said his state's voters had months to compare and contrast the candidates.

"Tonight, the Democratic voters of South Carolina have rendered a significant verdict," Clyburn said at Clinton's victory rally in Columbia.

NBC Projects Hillary Clinton Wins Big in South Carolina 1:28

Clinton has now demonstrated massive victories among African Americans in two very different states on opposite sides of the country — Nevada and South Carolina — suggesting that their loyalty to her, and the so-called firewall built on that loyalty, will hold.

The margins raise the real possibility Clinton could take a major pledged delegate lead in next week's Super Tuesday contests, when six southern states with large African-American populations will hold nominating contests at once.

Even under the rosiest scenarios for Sanders, it will be hard for him to catch Clinton on Super Tuesday.

Sanders was not in South Carolina Saturday night, instead campaigning in Minnesota ahead of that state's Tuesday primary. But in a statement released shortly after polls closed, the Vermont senator vowed to continue his fight.

"Let me be clear on one thing tonight. This campaign is just beginning. We won a decisive victory in New Hampshire. She won a decisive victory in South Carolina," Sanders said. "Our grassroots political revolution is growing state by state, and we won't stop now."

Sanders' supporters were braced for the loss, but the drubbing will be a test of his small-dollar fundraising apparatus, which is the lifeblood of his campaign.

Clinton Declares Victory in South Carolina Primary 15:41

Clinton supporters, meanwhile, are likely to begin urging Sanders to drop out of the race so she can begin to focus on the general election.

"I don't see a path forward for Bernie Sanders. The sooner he gets out the better," said Boyd Brown, a Democratic National Committee member from South Carolina who supports Clinton.

At a high-energy victory party in massive gymnasium here, Clinton beamed as she took the stage to chants of "madam president!"

The former secretary of state suggested she was looking to the next phase of the campaign, the general election campaign after that, and even her potential presidency. "Tomorrow, this campaign goes national," she declared.

With exit polls showing that Clinton won black voters by an even larger margin than Barack Obama beat her with in 2008, the win bolsters her plan to reassemble the divers coalition that twice put President Obama in the White House for a third Democratic win.

"Despite what you hear, we don't need to make America great again — America has never stopped being great," Clinton said, making it clear she was already setting at least one eye on Donald Trump, the Republican front-runner.

This article first appeared on MSNBC