Sen. Bernard Sanders on Wednesday suspended his presidential bid, paving the way for Joseph R. Biden’s coronation as the 2020 Democratic presidential nominee and leaving far-left voters mulling their options.

Mr. Sanders said he came to grips with the “painful” reality that he no longer had a feasible path to the nomination and that he couldn’t in good conscience push ahead amid the COVID-19 pandemic.

“So 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,” Mr. Sanders said in a livestream from his home state of Vermont. “So today I’m announcing the suspension of my campaign.

“While this campaign is coming to an end, our movement is not,” he said. “The fight for justice is what our campaign has been about. The fight for justice is what our movement remains about.”

The announcement set the stage for the long-anticipated general election showdown between President Trump and Mr. Biden.

The former vice president faces the challenge of unifying the party around his bid. Far-left and young voters who flocked to Mr. Sanders‘ vision for the nation are skeptical of Mr. Biden’s bid.

Mr. Biden sought to bridge that gap Wednesday by praising Mr. Sanders for creating a political movement that has driven the national conversation on issues such as climate change, universal health care and student debt relief.

“While the Sanders campaign has been suspended, its impact on this election and on elections to come is far from over,” Mr. Biden said.

“More than any one issue or set of issues, I want to commend Bernie for being a powerful voice for a fairer and more just America,” he said.

Mr. Trump also pursued Mr. Sanders‘ supporters in his typical bold fashion. He blamed Sen. Elizabeth Warren of Massachusetts, who accused Mr. Sanders of saying a woman couldn’t win the White House, for sinking his bid, and he poked at the wounds of 2016 when leaked emails showed Democratic National Committee staffers preferred Hillary Clinton to Mr. Sanders.

“Thank you to Elizabeth Warren,” Mr. Trump said on Twitter. “If not for her, Bernie would have won almost every state on Super Tuesday!”

“This ended just like the Democrats & the DNC wanted, same as the Crooked Hillary fiasco. The Bernie people should come to the Republican Party, TRADE!” he tweeted.

The suspension of Mr. Sanders‘ bid marks the end of a quest for the White House that began five years ago when he announced his long-shot bid for the Democratic presidential nomination.

Defying expectations, he won 23 contests against Mrs. Clinton and developed a grassroots “revolution” that shifted the Democratic Party further to the left by adopting, among other issues, a $15-per-hour minimum wage, tuition-free college and “Medicare for All.”

“It was not long ago that people considered these ideas radical and fringe,” Mr. Sanders said Wednesday. “Today they are mainstream ideas.”

The movement helped the likes of Rep. Alexandria Ocasio-Cortez, the liberal firebrand from New York City who volunteered for Mr. Sanders‘ 2016 campaign before knocking off one of the top House Democrats in the 2018 midterm primaries.

Mr. Sanders was far better prepared this time. He had a national brand and a grassroots fundraising network that was unmatched in the nomination race.

But he faced a much broader field of contenders — many of whom had adopted signature parts of the far-left platform that he popularized.

Mr. Sanders started the race with a bang.

He finished a close second in the Iowa caucuses before rattling off a pair of clear-cut victories in New Hampshire and Nevada that gave him a surge of momentum heading into South Carolina.

His success, however, scared the less-liberal ranks of the party, who worried that his brand of democratic socialism would be too extreme for much of the nation, making it harder to oust Mr. Trump and strengthen Democrats’ numbers in Congress and statehouses across the country.

The race changed dramatically after Mr. Biden easily won South Carolina. Soon afterward, he picked up endorsements from three of his former rivals: former South Bend, Indiana, Mayor Pete Buttigieg, Sen. Amy Klobuchar of Minnesota and former Rep. Beto O’Rourke of Texas.

Mr. Biden followed that up with a dominant performance on Super Tuesday and went on to victory in Michigan, which Mr. Sanders won in 2016.

Making matters worse, exit polls showed Mr. Biden winning states where a majority of Democrats aligned with Mr. Sanders‘ ideas.

Then the coronavirus outbreak froze the campaign.

“I know there may be some in our movement who disagreed with this decision, who’d like us to fight on to the last ballot cast at the Democratic convention. I understand that position,” Mr. Sanders said.

“But as I see the crisis gripping the nation exacerbated by a president unwilling or unable to provide any kind of credible leadership and the work that needs to be done to protect people in this most desperate hour, I cannot in good conscience continue to mount a campaign that cannot win and which would interfere with the important work required of all of us in this difficult hour,” he said.

Mr. Sanders described Mr. Biden as a “very decent man” and vowed to work with him “to move our progressive ideas forward.”

Others said it will be difficult for Mr. Biden to get Mr. Sanders‘ supporters excited about his campaign.

“They are more likely to stay home,” said RoseAnn DeMoro, former executive director of National Nurses United and a vocal Sanders backer. “It would take something set in stone that is real change, which the [corporate backers] will stop.”

Eight liberal groups, including the Justice Democrats and NextGen America, wrote an open letter urging Mr. Biden to make commitments to excite young voters.

They demanded that he block current or former Wall Street executives from serving in his Cabinet, create a post for a national director of gun violence prevention, and pledge to appoint a director of homeland security who is committed to “dismantling” Immigration and Customs Enforcement and U.S. Customs and Border Protection “as we know them.”

“The victorious ‘Obama coalition’ included millions of energized young people fighting for change,” the letter says. “But the Democratic Party’s last presidential nominee failed to mobilize our enthusiasm where it mattered. We can’t afford to see those mistakes repeated.”