WASHINGTON — Vermont Senator Bernie Sanders dropped out of the presidential race on Wednesday, ceding the Democratic nomination to his moderate rival Joe Biden and raising questions about the future of the progressive movement that propelled the democratic socialist’s rise.

Sanders told his supporters that he had made the “difficult and painful” decision to end his campaign in order to devote more time to dealing with the coronavirus crisis that has reshaped the 2020 general election. He acknowledged he no longer saw a path to victory against Biden, who built a large delegate lead before the outbreak effectively froze the Democratic contest.

“While we are winning the ideological battle and while we are winning the support of so many young people and working people throughout the country, I have concluded that this battle for the Democratic nomination will not be successful,” Sanders said in a livestream address from his Burlington home on Wednesday.

Sanders did not explicitly endorse Biden, but did call the former vice president a “decent man” and said he looked forward to working with him, suggesting an official endorsement will likely follow.

Sanders also hinted that Biden will need his help to motivate the younger wing of the party that rallied behind Sanders’ progressive vision of Medicare for All and a Green New Deal. “The future of this country is with our ideas,” he said, noting that he won majorities of younger voters in the primary against Biden. Sanders vowed to remain on the ballot in future contests to continue amassing delegates to exert leverage over the party’s platform.

Biden released a lengthy statement praising Sanders’ efforts to change the status quo and appealing to his backers. “To your supporters, I make the same commitment: I see you, I hear you, and I understand the urgency of what it is we have to get done in this country,” Biden said.

The positive statements from both men appeared aimed at heading off a rift in the party similar to one that plagued Democrats in 2016, when Sanders supporters protested at the Democratic National Convention despite his endorsement of Hillary Clinton. But it’s clear many liberals still expect more concessions from Biden.

"Messaging around a ‘return to normalcy’ does not and has not earned the support and trust of voters from our generation,” a group of young progressive activist leaders wrote on Wednesday, urging Biden to adopt more sweeping proposals on climate change and to commit to appointing progressives to his administration.

Just a few months ago, it appeared Sanders’ vision of sweeping change might actually carry him to the nomination. He amassed the biggest financial war chest in the Democratic primary from grass-roots donations alone and shifted the race’s center of gravity to the left with his populist rhetoric targeting millionaires and billionaires. Despite suffering a heart attack last October, he attracted thousands of passionate young fans at rallies around the country, and became the race’s front-runner after winning the New Hampshire and Nevada primaries in February.

But Sanders, 78, faced a stunning reversal of fortune after Biden, 77, won by a landslide in the South Carolina primary on Feb. 29 and swept most states voting on Super Tuesday on March 3. Sanders made inroads with Latino voters that helped him win the delegate-rich state of California, but he was unable to make up his deficit with Black and suburban voters.

In recent weeks, Sanders had ceased fund-raising for his presidential bid entirely and effectively shut down his campaigning. He instead raised millions for coronavirus aid efforts and publicly pushed for expanded workers’ rights and universal health care to combat the crisis.

Democratic Party insiders fretted that his continued candidacy was hurting the future nominee, as some in Sanders’ circle sharply criticized Biden’s lack of visibility and skills as a candidate. But Sanders’ allies said he wanted to stay in the fight to gain leverage for his movement and ensure the party’s platform continues to lean left.

Sanders’ decision frees Biden to focus exclusively on his battle with President Trump, and also allows former president Barack Obama, who vowed to remain neutral during the primary, to finally endorse his former running mate.

At a virtual fund-raiser on Wednesday, Biden told donors he sought Obama’s advice on his own vice presidential search and is looking for “a woman vice president who has the capacity, has strengths where I have weaknesses.” At a later virtual fund-raiser with California Senator Kamala Harris, Biden fueled rumors he might pick her as his running mate by praising their “partnership” and her loyalty to him.

An Obama endorsement and a vice presidential pick could boost enthusiasm for Biden, who struggled to attract large crowds during the primary and has since been relegated to broadcasting from a home studio in his basement due to social distancing restrictions.

Biden will also need to win over Sanders supporters who are suspicious of his more moderate agenda. The president has attempted to stir up resentment among Sanders fans, calling the primary “rigged” against him on Twitter. But privately, Trump appeared to fear running against Biden more, even pressuring Ukraine to investigate Biden and his son Hunter in a covert effort that led to Trump’s impeachment.

“Can’t see AOC plus 3 supporting Sleepy Joe!” Trump tweeted shortly after Sanders’ address, referring to the liberal members of the House, including Representative Alexandria Ocasio-Cortez, who endorsed Sanders. But one of those members, Representative Ilhan Omar of Minnesota, had already delivered the opposite message to her supporters. “For those of you who plan to sit this election out or vote for Trump, just stop,” she wrote.

The departure of Sanders is also a moment of reckoning for the progressive movement, which had been rejoicing over how his policy proposals like the Green New Deal, Medicare for All, and free college entered the party’s mainstream after his 2016 run. But in a year when most Democrats said beating Trump was their top priority, Biden ended up capturing more voters with a message of “restoring” the soul of the nation than Sanders did with a call for revolution and systemic change.

Many of Sanders’ allies believe he was inundated with unfair attacks after his Nevada win, with dozens of the party’s superdelegates telling The New York Times they would oppose his nomination even if he won a plurality of delegates and some Democrats and pundits warning he would lose to Trump because he’s too far to the left. Those Sanders supporters see the backlash as a manifestation of deep opposition from the corporate “establishment” that Sanders often warned crowds about at his packed rallies.

“The amount of money that gets poured into all these lobbies is a huge burden to overcome and the left has seen that up close in two presidential contests,” said James Zogby, a board member of the Sanders-aligned group Our Revolution. “We know that these are the obstacles that we’ve got to fight.”

But chief among Sanders’ obstacles was his inability to make inroads with many Black voters who also spurned him in 2016, despite his ramped-up outreach this time around. Another progressive candidate, Senator Elizabeth Warren, also failed to attract many Black voters, suggesting a larger hurdle for progressives in their quest for the White House.

“As a whole the left has a real vulnerability with Black communities in the South,” said Ana Maria Archila, who leads the Center for Popular Democracy grass-roots group, which backed Sanders. “We have not built strong individual organizations there.”