Following Bernie Sanders’s victory in New Hampshire, supporters are optimistic that the ‘Bern’ will gain momentum and spread to South Carolina and Nevada next. They also couldn't help but dance throughout the rally, going as far as dedicating some serious dance moves to the senator. (Alice Li/The Washington Post)

Sen. Bernie Sanders scored a decisive victory in Tuesday’s New Hampshire presidential primary, embarrassing Hillary Clinton in a state she won eight years ago and upending the Democratic nominating contest.

Sanders’s victory, which Clinton conceded when polls closed at 8 p.m., confirmed the strength of his iconoclastic appeal and the power of an insurgent message that cast Clinton as a creature of the old guard. The outcome provides a fresh burst of momentum for Sanders, a senator from Vermont, in a race that will soon broaden to more challenging terrain and that is widely expected to grow more combative as Clinton tries to regain her footing. The former secretary of state, who was declared the winner of the Iowa caucuses last week by the narrowest of margins, now finds herself struggling to right her ­once-formidable campaign against a self-described democratic socialist whom she has accused of selling pipe dreams.

“People have every right to be angry, but they’re hungry. They’re hungry for solutions,” Clinton said in a brief concession speech shortly after she called Sanders to congratulate him. “What are we going to do? That is the fight we’re taking” to the rest of the country.

Sanders’s lengthy victory speech focused on his core issues of Wall Street greed and income inequality, but also ranged to national security, immigration, Social Security and more. He told cheering supporters that the same improbable arc that brought him to victory here can happen across the country.

“What began last week in Iowa, what voters confirmed here tonight, is nothing short of the beginning of a political revolution,” Sanders said. “We will all come together to say loudly and clearly that the government of our great nation belongs to all of us, not just a few wealthy campaign contributors.”

Democratic presidential candidate Hillary Clinton emphasizes campaign finance reform and economic policy as she spoke to supporters after conceding to Bernie Sanders in the New Hampshire primary. (Reuters)

Shortly before midnight, with roughly three-quarters of precincts tallied, Sanders had a huge, double-digit lead. Four hours earlier, a Clinton campaign memo was released as the polls closed stating that the loss was “long anticipated.”

“Attention will inevitably focus on the next two of the ‘early four’ states: Nevada and South Carolina,” Clinton campaign manager Robby Mook wrote. “We’ve built first-rate organizations in each state and we feel very good about our prospects for success” there and in states that vote in March, the memo stated.

Sanders planned to challenge those assumptions immediately. He was scheduled to leave New Hampshire late Tuesday and head to New York for a day-long victory lap. Following a breakfast with civil rights leader and television host Al Sharpton, Sanders is scheduled to appear on “The View” and “The Late Show With Stephen Colbert,” among other media appearances.

The meeting with Sharpton is part of an effort to widen Sanders’s support among African American voters, who will figure prominently in several upcoming primaries in Southern states — and who have favored Clinton by broad margins in polls.

Clinton is racing to shore up that advantage by turning next to states with large minority populations. She has scheduled campaign stops in South Carolina and Nevada in the next week, with an emphasis on criminal justice and gun control, issues on which she has attempted to get out ahead of Sanders or to his political left. Her campaign also announced new support from African American mothers who have lost children to gun violence and said some of the women would campaign for Clinton in South Carolina.

The fundraising race will also intensify — and already had, shortly after the race was called Tuesday.

Even before Sanders took the stage Tuesday night to acknowledge his victory, his campaign sent out a text message to supporters saying: “With your help, we were just declared the winner in New Hampshire! Reply GIVE to contribute $10 from your phone bill and keep up the momentum.”

In addition, a fundraising email sent out by Sanders on Tuesday night warned of the tough fight ahead: “There are 14 primaries and caucuses over the next three weeks, and you can be certain that our victory tonight will prompt a desperate response from the nation’s financial elite and the political establishment who want to stop our campaign to transform America.”

Clinton’s campaign sent out an email fundraising appeal that presaged her poor showing and looked ahead. “We absolutely, critically need to make sure Hillary comes out on top in the states that lie ahead,” the email said. “Our opponent is raising massive amounts of money online, and we need everyone on Team Hillary to step up, too.”

Sanders was written off as a fringe candidate when he launched his bid last spring against one of the best-known Democrats in the country. But in New Hampshire, even more so than in Iowa, Sanders found a receptive audience for his populist, anti-establishment message.

He has vowed to curb the corrupting influence of money in politics and power of Wall Street while rebuilding the American middle class by offering free college tuition, universal health care and an array of other programs.

Clinton’s campaign had been lowering expectations for New Hampshire, based largely on what Clinton called a “neighborly” impulse, although Sanders’s appeal here cannot be chalked up to that alone. Clinton trailed by an average of 15 points in major polls going into the nation’s first primary vote, and she ran an underdog campaign here in the closing weeks. Her campaign had watched as a 30-point lead here dwindled and then evaporated late last year.

Sanders’s appeal Tuesday was greatest among younger voters, according to exit polls reported by CNN and other networks. He also benefited from New Hampshire’s open primaries, which allow independents to vote in either the Democratic or Republican contests, winning roughly 7 in 10 not registered as Democrats.

Sanders also won decisively among male voters and more than held his own among female voters against Clinton, who would be the first woman to serve as president, a fact several of her high-profile boosters made a central part of their appeal in recent days.

The Democratic race now moves to Nevada, which holds caucuses on Feb. 20, and then South Carolina, which holds a primary on Feb. 27. After that, 11 states hold contests on March 1, known as Super Tuesday.

Clinton and Sanders have spent much of the year courting largely white electorates in Iowa and New Hampshire, but the next two states will test their abilities to connect with Latinos and African Americans. Clinton is well known among both key Democratic constituencies, while Sanders, who represents a state that is 95 percent white, has been laboring to make inroads with both groups.

His campaign manager, Jeff Weaver, said Sanders believes those efforts — which include Spanish-language radio ads in Nevada and an army of paid door-knockers in South Carolina — will pay off in coming weeks. He should also get a boost from the win Tuesday, Sanders said.

“For many voters, there was a question about whether Senator Sanders’s message and his campaign could go toe to toe with the Clinton organization, and I think in Iowa he proved that we could,” he said. “A victory in New Hampshire further amplifies that reality to voters all across the country.”

Sanders also faces a challenge as the playing field expands and the race starts moving more quickly. He benefited from sustained ground campaigns in Iowa and New Hampshire, which led to a greater familiarity among voters. That luxury soon disappears, as candidates must hopscotch around the country and the race becomes far more dependent on TV advertising.

Despite her expected loss, Clinton was upbeat Tuesday morning and she and daughter Chelsea dropped in on polling places in Manchester and Nashua. Clinton

volunteers lined up at Parker Varney School here chanted “6-0-3 for H-R-C,” using the New Hampshire area code.

“As I’ve said over the past couple days, we’re going to keep working, literally, until the last vote is cast and counted, and we’re going to go from there,” she told NBC.

When her double-digit lead slipped last fall, Clinton’s biggest boosters in New Hampshire insisted it was a temporary dip, reflecting restlessness within an electorate that would ultimately return to the candidate best prepared to be president. Clinton got off to a three-month head start over Sanders airing television ads in the state, and in the closing days of the contest, both she and her husband and daughter were fixtures on the campaign trail, doing all they could to promote her and undermine Sanders. Bill Clinton unloaded on Sanders in a speech Sunday, accusing Sanders’s followers of sexism and his campaign of fabricated attacks.

On Monday, Hillary Clinton sought to turn the tables on Sanders, who for weeks had highlighted the millions of dollars in campaign contributions and speaking fees she received from Wall Street firms to call into question whether she is prepared to reform the financial sector.

Clinton suggested Sanders was being hypocritical because he accepted “about $200,000” from Wall Street firms through the Democratic Senatorial Campaign Committee. Weaver dismissed that suggestion as a sign of an opposing campaign in “disarray.”

The fight is expected to get nastier as the stakes get higher. Already, Clinton and her surrogates have questioned Sanders’s record on gun control, his commitment to reproductive rights and other women’s issues, and the feasibility of his call to move to a single-payer “Medicare for all” health program.

Despite vows to get money out of politics, Sanders’s campaign has not suffered from a lack of resources. In the two most recent fundraising quarters, he nearly matched Clinton’s haul. Sanders’s campaign recently announced it had taken in an eye-popping $20 million in January — $5 million more than Clinton — and $3 million in just the 24 hours that followed his near-tie in the Iowa caucuses.

Aides said they were prepared for a fresh wave of donations after a New Hampshire victory. His take, fueled by hundreds of thousands of small online donations averaging $27 apiece, enabled Sanders to put on a robust television advertising campaign in New Hampshire that exceeded Clinton’s in the closing weeks.