Bernie Sanders is no longer running for president, making Joe Biden the Democratic Party's presumptive nominee.

The socialist Vermont senator suspended his campaign after repeated primary contest losses showed that he had no viable path to the Democratic presidential nomination against Biden.

Sanders announced his decision to drop out in an all-staff call on Wednesday morning, the day after Wisconsin's Democratic presidential primary. A press release noted that while "the campaign ends, the struggle continues."

"I wish I could give you better news, but I think you know the truth, and that is that we are now some 300 delegates behind Vice President Biden, and the path toward victory is virtually impossible," Sanders said in a livestream address to supporters.

The former vice president decisively won many states that Sanders captured in 2016, such as Michigan, Oklahoma, Minnesota, and Maine.

Sanders suggested that the coronavirus pandemic, which prevented him from holding traditional campaign rallies and get-out-the-vote efforts in the last weeks of his campaign, contributed to his decision to suspend his operation rather than continue to fight for the nomination through the Democratic National Convention.

"As I see the crisis gripping the nation," Sanders said, "I cannot in good conscience continue to mount a campaign that cannot win and which would interfere with the work required of all of us in this difficult hour."

Sanders said, however, that he will stay on future primary ballots and will "continue to gather delegates" to the Democratic National Convention this summer, saying that his supporters must be "working to assemble as many delegates as possible to exert significant influence over the party platform."

After the first three primary contests, Sanders was dominant in the race. He was a close second to former South Bend, Indiana, Mayor Pete Buttigieg in Iowa and won New Hampshire and Nevada. But after Biden won South Carolina in a blowout, Buttigieg and Minnesota Sen. Amy Klobuchar quickly dropped out of the race and endorsed Biden, coalescing more centrist opposition to Sanders's socialist vision and allowing Biden to amass a delegate lead that Sanders could not break.

Sanders campaigned for the Democratic nomination for the second time on a socialist platform and popularized Medicare for All, a plan to create a government-funded healthcare system that would make virtually all private insurance plans illegal. That embrace of socialism and rejection of private insurance, along with an admission that his plan would raise taxes on middle-class households, sparked heavy criticism from more centrist primary rivals.

"It was not long ago that people considered these ideas radical and fringe. Today, these are mainstream ideas, and many of them are being implemented in cities and states across the country," Sanders said in his livestream Wednesday. "Together, we have transformed American consciousness as to what kind of nation we have become and taken this country a major step forward in the never-ending struggle for economic justice, social justice, racial justice, and environmental justice.”

The 78-year-old briefly suspended campaign activities after he had a heart attack in early October. Doctors discovered a blockage in an artery and inserted two stents after he was taken to the hospital for chest pains during a Las Vegas campaign rally.

Equipped with high name recognition and a large list of supporters from his 2016 presidential bid, when he lost the Democratic nomination to Hillary Clinton, the Sanders campaign amassed 1 million donors by September 2019.

Massachusetts Sen. Elizabeth Warren espoused many of the same liberal policy ideas as Sanders without the socialist label and, for a time, surpassed him in Democratic primary polls. The independent Vermont senator, who caucuses with the Democratic Party, won the endorsement of rising liberal star Rep. Alexandria Ocasio-Cortez and other recently elected congressional Democrats.

Sanders was the oldest candidate in the crowded Democratic presidential field and would have been the oldest president ever had he been elected. President Ronald Reagan was 77 when he left office in 1989. He is slightly older than Biden and former New York City Mayor Michael Bloomberg, both of whom are 77.

Sanders's Senate term lasts through the 2024 elections.