RINDGE, N.H. (AP) - Joe Biden and Bernie Sanders are taking strikingly different approaches in the final hours before New Hampshire’s first-in-the-nation presidential primary, underscoring the uncertainty around Democrats’ search for a challenger to take on President Donald Trump in November.

Sanders, a Vermont senator, embraced high expectations Monday in his neighboring state. “If we win here tomorrow, I think we’ve got a path to victory for the Democratic nomination,” Sanders declared in Rindge.

Biden, alternately, lowered expectations as he faces the prospect of finishing well off the pace for the second time after opening the 2020 election season with a fourth-place finish in the Iowa caucuses. The former vice president, once the clear national front-runner, warned in a morning CBS interview that “this is just getting started,” reminding voters that he has shown strong support among African Americans and Latinos who will hold sway in the states that follow New Hampshire in voting.

Biden’s challenge and Sanders’ optimism about the opening states highlights a larger concern for Democrats as they look for a standard-bearer: No would-be nominee has proved an ability to build a strong coalition across the party’s various racial, ethnic and ideological factions. That situation is muddled further by the vote-tabulation melee in last week’s Iowa caucuses that left both Sanders and Pete Buttigieg claiming victory. Neither reached 30% of the vote in a fractured field.

Trump, meanwhile, is eager to cast a shadow over the entire Democratic slate as he heads to Manchester for a Monday evening rally to continue his victory-and-vengeance tour following Senate votes that acquitted him on two impeachment charges. Trump lost New Hampshire in 2016 by fewer than 3,000 votes out of more than 743,000 cast, and the state is among several his reelection campaign believes it can flip in November.

Trump's supporters began lining up in New Hampshire on Sunday, and the crowd only grew despite freezing, wet weather. The president managed a similar scene in Iowa days ahead of the caucuses, drawing thousands of boisterous supporters who contrasted with a lower-than-expected caucus turnout for Democrats.

Against that backdrop, Biden insisted Monday that he remains well-positioned for the nomination and to defeat Trump in November. He pointed to endorsements from the International Brotherhood of Electrical Workers and Michigan’s legislative black caucus that he’s gotten since the Iowa caucuses. “I’m still leading nationally,” Biden told CBS, referring to months of national polls, though it’s far from certain that Biden will remain in such a position in the coming weeks.

Biden also sought not to abandon hope in New Hampshire, offering voters in Gilford a spirited takedown of the Republican president. “I’ll be damned if I’m going to stand by and watch us lose this country to Donald Trump a second time,” Biden said in a speech largely ignoring his Democratic competitors.

It could depend on voters like Pat Barrick, a 70-year-old independent who said she was once solidly with Biden but now is also considering Minnesota Sen. Amy Klobuchar, who finished just behind Biden in Iowa and has since seen a bounce in New Hampshire.

“He matches my values,” Barrick said of Biden. “I just don’t know if he can win.”

Indeed, no Democrats have managed to separate themselves from the pack.

Sanders and Buttigieg are vying for momentum that could dent Biden’s claims to national support. But Sanders, a democratic socialist, has virtually no support from the party’s center-left core, and some establishment figures openly fret about Sanders leading the ticket in November.

Buttigieg draws large crowds with his calls for generational change, but the 38-year-old former mayor of South Bend, Indiana, hasn’t demonstrated significant support from African American or Latino voters, who will become significant parts of the Democratic electorate in the states that follow New Hampshire. And several of Buttigieg's rivals, Biden included, have started hammering his comparatively thin resume.

In Plymouth on Monday, a top Buttigieg backer met that criticism directly to open a Buttigieg event. “He has an executive’s temperament. It’s not a legislative job,” said Gary Hirshberg, an influential New Hampshire Democrat who was a key early supporter of Barack Obama’s 2008 campaign. “Pete Buttigieg has more executive experience than Barack Obama did before he was president.”

Racial diversity is also a question for Klobuchar. She could deliver Biden a new blow if she leapfrogs him in New Hampshire, but it’s unclear whether her campaign has the national reach to capitalize on any newfound momentum heading toward the March 3 Super Tuesday slate, when more than a third of Democrats’ approximately 4,000 pledged delegates will be up for grabs.

In Nashua on Monday, Klobuchar declared 2020 “a decency test” for the nation. Loosely quoting the 19th-century author Alexis de Tocqueville, she said, “America … may not be the most enlightened nation, but America is always a country that finds a way to repair its faults.”

Massachusetts Sen. Elizabeth Warren, meanwhile, has shown flashes of a broad coalition, as she tries to compete with Sanders on the party’s left flank and with Buttigieg for more moderate white college graduates. She’s added a relatively new argument in New Hampshire, pitching herself as the candidate who can best unify the party. But she and Biden face a potential money crunch if donors are spooked by Tuesday's results in New Hampshire's primary.

Beyond New Hampshire, billionaire Michael Bloomberg continues his unusual strategy of skipping the four states that vote in February and plowing hundreds of millions of dollars into Super Tuesday states. Bloomberg’s centrist candidacy hinges largely on Biden underperforming and the proposition that neither Buttigieg nor Klobuchar can fill the gap. His campaign on Monday announced new staff investments in Utah and Colorado, bringing his national footprint to 2,100 staffers, with 18 states boasting at least 40 employees.

Despite the questions facing the Democratic field, New Hampshire Democratic Chairman Ray Buckley said he remains optimistic about their chances of toppling Trump, even going so far as to welcome the president’s Monday visit.

“His ego can’t stand the idea of something going on and he’s not in the middle of it,” Buckley told reporters. “It has backfired on him before, and I believe it’s going to backfire on him this time.”

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Barrow reported from Atlanta. Associated Press writers Thomas Beaumont in Plymouth, N.H., Hunter Woodall in Gilford, N.H., Michael Casey in Nashua, N.H., and Alexandra Jaffe in Des Moines, Iowa, contributed to this report.

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