WASHINGTON (AP) — Joe Biden swept to easy victories in Florida and Illinois on Tuesday, increasingly pulling away with a Democratic presidential primary upended by coronavirus and building pressure on Bernie Sanders to abandon his campaign.

The former vice president’s third big night in as many weeks came amid tremendous uncertainty confronting the Democratic contest as it collides with efforts to slow the spread of the virus that have shut down large swaths of American life. Polls were shuttered in Ohio, and although balloting went ahead in Florida, Illinois and Arizona, election workers and voters reported problems.

Biden’s quest for his party’s nomination now seems within reach. He needs less than half of the remaining delegates to become the nominee. The party establishment has increasingly lined up behind him, meanwhile, as the best option in November to try and unseat President Donald Trump.

“Our campaign has had a very good night and is a little closer to securing the Democratic nomination,” Biden said after his latest two primary victories.

Also Tuesday, Trump formally clinched the Republican presidential nomination against minimal opposition — a measure of good if not unexpected news for a White House trying to cope with the public health and economic crisis sparked by the coronavirus.

Results aside, the Democratic primary has remained largely in limbo, with rallies and big events canceled. That has given Sanders, whose pathway to the nomination has greatly narrowed, even less room to maneuver, unable to convene the large crowds across the country that are his trademark.

Some Democrats are now calling on him to leave the race in the name of party unity. But Sanders made no mention of that Tuesday night in a livestream to supporters. The Vermont senator has instead promoted calls for universal, government-funded health care under his signature “Medicare for All” plan. Top advisers say he’s betting that the national political landscape could look different as the virus continues to reshape life across the country.

During the coronavirus outbreak, “We must make sure everyone who has a job right now receives the paychecks they need,” Sanders said in an online appearance that started before Tuesday’s polls had even closed.

Biden maintained the strength with African Americans and older voters that has been the hallmark of his campaign but also appeared to chip away at Sanders’ previous advantage with Hispanics that helped him win Nevada and California early in the race. In Florida, Latinos were roughly 20% of Democratic primary voters, and they largely sided with Biden, with the former vice president getting the support of 65% of Puerto Rican voters and 56% of Cubans, according to AP VoteCast, a broad survey of voters.

Turnout in Florida’s Democratic primary was higher than it was four years ago, when 1.7 million voters cast ballots. This time, turnout was on pace to approach 2 million. Still, reports of havoc wreaked by the coronavirus dominated the day.

Officials in Ohio took the unprecedented step of closing polls Monday, mere hours before they were set to open, pushing back the state’s primary until June.

Democratic National Committee Chairman Tom Perez blasted the move for breeding “more chaos and confusion” and sought to head off more states taking similar actions, urging those with upcoming primaries to expand vote-by-mail and absentee balloting, as well as polling station hours.

The fear is that the spread of the coronavirus derails his party’s nomination contest.

“The right to vote is the foundation of our democracy, and we must do everything we can to protect and expand that right instead of bringing our democratic process to a halt,” Perez said in a statement.

The damage, though, may already have been done. Four other states — Louisiana, Georgia, Kentucky and Maryland — have already moved to push back their upcoming primaries, and others may yet do so. That has left the Democratic primary calendar empty until March 29, when Puerto Rico is scheduled to go to the polls — but island leaders are working to reschedule balloting there, too.

That means, there is nowhere for Sanders to gain ground on Biden anytime soon, even if he could find a way to mount a sudden surge.

In the meantime, voting Tuesday saw problems pop up across the country. In Okaloosa County in Florida’s Panhandle, two dozen poll workers dropped out, leaving Elections Supervisor Paul Lux’s staff scrambling to train replacements.

“We are at the honest end of the rope,” Lux said.

Political observers say the coronavirus has cast a shadow over the race as debates over policy minutiae have taken a back seat to issues of life and death.

“It’s definitely eerie,” said Jesse Lehrich, a Democratic operative and former Hillary Clinton campaign spokesman who is based in Chicago, who added, “Biden and Sanders are debating the merits of marginally different policies in this little pseudo-reality, while America is consumed by an unprecedented crisis.”

Millions of voters have already participated in some form of early voting. But there were signs on Tuesday that voters — and poll workers — had stayed home.

“People are prioritizing their day-to-day survival right now — so they’re not thinking of voting as a priority,” said Debra Cleaver, the founder of Vote.org.

In Florida, Palm Beach County Elections Supervisor Wendy Sartori Link said three polling sites had to be moved and four opened significantly late because workers didn’t show up and hadn’t given notice.

“We probably should have been expecting it more than we were,” she said.

In Illinois, there was a push to relocate about 50 Chicago-area polling places after locations canceled at the last minute.

Jim Allen, a spokesman for the Chicago Board of Election Commissioners, said Tuesday that the board asked Gov. J.B. Pritzker last week to cancel in-person voting, but the governor refused. Pritzker countered that state law doesn’t give him the authority to make the sweeping changes that elections officials wanted.

“Let me tell you this: It is exactly in times like these when the constitutional boundaries of our democracy should be respected above all else. And if people want to criticize me for that, well, go ahead,” the governor said.

There weren’t problems, everywhere, though. Mel Dockens, a 49-year-old small-business owner, voted in the Phoenix suburb of Glendale and said it was a tough choice. But he went for Biden because he thought Sanders’ progressive views might turn off some Democratic voters.

“It’s all about electability,” Dockens said. “It’s not that I don’t trust Bernie Sanders, but I trust (Biden) a little more.”

Associated Press writers Christina Cassidy and Bill Barrow in Atlanta, Katie Foody in Chicago, Kelli Kennedy and Terry Spencer in Fort Lauderdale, Fla., Don Babwin in Burbank, Ill., and Seth Borenstein and Alexandra Jaffe in Washington contributed to this report.