NEW YORK — Can Vermont Sen. Bernie Sanders recapture the magic that fueled his first presidential campaign?

To win the nomination, he may not need to.

As Sanders, a 77-year-old self-described democratic socialist, formally launches his 2020 campaign, the lessons of President Donald Trump’s victory in the GOP’s packed 2016 contest loom large.

With better-established Republican contenders dividing the GOP primary vote that year, Trump began racking up primary victories with 30 to 40 percent of each state’s vote. He captured his party’s nomination even as six or seven of every 10 primary voters backed another Republican candidate.

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Sanders’ team is betting that the bar for victory in the more-crowded 2020 Democratic field could be even lower. That simple math — and an extraordinary small-dollar fundraising operation — suggests that Sanders is poised to maintain his status as a political force in 2020 whether most of his party wants him to or not.

Sanders is showing no desire to change his approach to broaden his appeal, as is sometimes the case with ambitious second-time candidates. Nina Turner, president of Our Revolution, the political arm of Sanders’ expansive network, said the 2020 campaign “is really about him finishing what he started.”

In a political world in which windows of opportunity rarely stay open long, it’s possible that Sanders’ moment may have passed.

In 2016, he was the sole option for anti-establishment Democrats who didn’t support Hillary Clinton. Today, Democrats are sorting through a far more diverse field that could ultimately exceed two dozen high-profile contenders. Many of them — and there are exceptions — have adopted Sanders’ far-left policy priorities and anti-establishment rhetoric.

Signs of erosion are easy to find.

While many grassroots activists cheered Sanders’ decision, New York Rep. Alexandria Ocasio-Cortez, another self-described democratic socialist and a worker for Sanders’ first presidential campaign, remained silent.

“We’re excited to see so many progressives in the race,” Ocasio-Cortez spokesman Corbin Trent said, declining to address Sanders’ big announcement directly. “We’re not thinking at all about the next election.”

Sanders enters a field that already includes progressive favorites like Massachusetts Sen. Elizabeth Warren, New Jersey Sen. Cory Booker and California Sen. Kamala Harris. They have adopted much of Sanders’ agenda to provide free universal health care, free college tuition and a $15 minimum wage. Still unknown is whether former Texas Rep. Beto O’Rourke or former Vice President Joe Biden will join the race, two prospects who could peel away some of Sanders’ base of support beyond the ultra-liberal wing of the party.

At the same time, Sanders has little hope of winning over many establishment-minded former Clinton supporters, still bitter from their perception that he didn’t work hard enough to defeat Trump once Clinton captured the Democratic nomination.

“Amazing how Bernie and his 3,708,294 fewer supporters squandered two years. They quadrupled down on their rigging rant and now there are 10 alternatives,” longtime Clinton adviser Philippe Reines tweeted. “Get ready to Feel the Fizzle.”

But it is Sanders’ consistency that has endeared him to a passionate base of liberal activists across the country who remain deeply loyal to him and his decadeslong fight for income equality and universal health care. Some of his competitors — particularly Warren and Harris — have also developed nationwide followings, but no one starts out with the same kind of fundraising appeal or organized network of like-minded groups such as Our Revolution, Justice Democrats and the Democratic Socialists of America.

“We’re more powerful than ever in the politics. We changed the game,” said 28-year-old Moumita Ahmed, the co-founder of Millennials Want Bernie 2020. “Bernie Sanders is still the only candidate that’s not the status quo.”

Anticipating Sanders’ decision, her organization had already organized chapters in Michigan, California, Nevada, New York, South Carolina and Washington state. She also donated $27 to Sanders on Tuesday, matching the often-touted average donation that fueled his first run.

Overall, Sanders raised more than $4 million from nearly 150,000 individual donors in the first 12 hours after launching his 2020 bid, his campaign said Tuesday.

Previously, the biggest first-day fundraiser in the race had been Harris, who raised $1.5 million in the first 24 hours of her campaign.

Even before Tuesday’s fundraising haul, however, Sanders had more cash in the bank than any of his competitors. He entered the contest with roughly $15 million to devote to his 2020 campaign, a combination of his Senate campaign fund and what’s left over from his 2016 presidential bid.

“Bernie Sanders is the front-runner,” tweeted former Clinton staffer Zac Petkanas. “Let’s see how he likes it.”

Indeed, with a higher profile comes higher scrutiny.

Sanders’ team expects to face more negative attention in his second run — both from rivals who view him as a legitimate threat and the broader political world that takes him seriously enough to devote more time and energy to dig deeper into his policies and personal background.

He will face particularly difficult questions over his campaign’s handling of allegations of sexual harassment and gender inequity during his 2016 campaign. The senator has already apologized and instituted a series of changes designed to prevent similar abuse in the future, but in a Democratic field that currently features more women than men, the issue is not going away anytime soon.

Former Vermont Gov. Howard Dean warned Democrats against underestimating Sanders.

“Bernie’s political career is littered with people who don’t take him seriously,” said Dean, who has encouraged Democrats to embrace a younger generation of candidates in 2020.

At the White House, meanwhile, Trump offered a mixed view of Sanders’ 2020 chances when asked during an unrelated event.

“Personally, I think he missed his time,” Trump said, even as he praised Sanders’ trade policies. “I wish Bernie well. It’ll be interesting to see how he does.”

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