The election in Pennsylvania is rocked by the uncertainty of a president stricken by coronavirus

President Donald Trump’s announcement Friday that he and his wife, Melania, had tested positive for the coronavirus jolted the race for the White House a month before Election Day, as both campaigns were forced to directly confront a public health crisis that has consumed the country and killed more than 207,000 Americans.

Trump, who went to Walter Reed National Military Medical Center for treatment on Friday, where the White House said he would spend a “few days,” will need to figure out how to campaign while isolated. His campaign said all previously announced events involving the president or his family were being moved to a virtual setting or postponed. Vice President Mike Pence, who tested negative, will resume scheduled campaign events.

The Biden campaign issued a statement Friday from the former vice president’s doctor saying Joe and Jill Biden had tested negative. He was set to fly to Michigan to deliver a speech later in the day.

The uncertainty came as both campaigns have been lavishing attention on the critical battleground state of Pennsylvania.

Biden this week took a chartered Amtrak tour through Western Pennsylvania, where he hopes to chip away at Trump’s support among rural and white working-class voters. Biden’s campaign events were socially distanced but included some of the largest crowds he’s seen since the pandemic began. His campaign was set to begin going door to door for the first time since then — something the Trump campaign has been doing for months.

Trump has held several large, mostly outdoor rallies in Pennsylvania over the last couple of months, where hundreds and sometimes thousands of supporters gather in close quarters — many without face masks, which Trump has often shunned. He was in Harrisburg for one rally on Saturday, and had been scheduled to appear in Philadelphia on Sunday before he tested positive.

It remains to be seen how Trump’s testing positive for a virus that has already hobbled him politically will affect the race between him and Biden, who has built a consistent and sizable lead in Pennsylvania and in national polls. And voting is already underway in Pennsylvania, with counties sending voters mail ballots. Philadelphia and other counties are also opening new elections offices where voters can request and submit mail ballots on the spot.

» READ MORE: Biden has a clear lead over Trump in Pa. as the 2020 election enters the homestretch

Lisa Walton, an Allentown Republican who is leaning toward Biden this year, said Trump’s diagnosis bolstered her belief that he has mismanaged the pandemic.

“He’s said one thing and done another this whole time,” said Walton, 55, a member of The Inquirer’s Election 2020 Roundtable of Pennsylvania voters. “He’s said wear masks, but then he doesn’t. He’s been out there, exposing himself without the proper protection, spending time around people. Eventually, it caught up to him.”

Judy Straight, 45, of McConnellsburg, in heavily Republican Fulton County, questioned whether Trump had done enough to protect himself.

“It’s sad he got it. I feel it’s because he didn’t wear his mask as much as he should have,” she said. “There’s a lot of people in our town that don’t.”

Still, she said, “I voted for him last time, and I’m going to vote for him again.”

» READ MORE: Biden ends his Amtrak tour with a message for blue-collar Pa. voters: Trump ‘doesn’t have a plan to help you’

The news again divided an already polarized electorate, which has been increasingly susceptible to misinformation. On social media and in call-in radio shows, some Democrats expressed skepticism Trump had actually contracted the virus. There is no evidence to suggest otherwise

Polls show most Americans disapprove of the president’s handling of the pandemic, and think Biden would better manage it. But the race has remained remarkably stable despite the virus, a punishing recession, nationwide protests against systemic racism, and a contentious political fight over replacing the late Supreme Court Justice Ruth Bader Ginsburg.

Trump’s diagnosis will again put the pandemic front and center, where Biden’s campaign has tried to keep it. Biden has taken a starkly different approach to campaigning during a public health crisis, for which he is often mocked by the Trump campaign. But the moment could also be a political tightrope for Democrats eager to elevate what they see as Trump’s inability to take the virus seriously while also showing compassion for Trump — who is now among the millions of Americans to contract it.

“It’s going to be challenging for the vice president,” said T.J. Rooney, a former Pennsylvania Democratic Party chairman. “How people react and how people perceive you of taking advantage of an unfortunate situation are all relevant considerations. ... They’re going to have to determine what the necessary balance is.”

One thing is clear, he said: Trump’s infection refocuses attention on the Trump administration’s “failures or shortcomings” in its pandemic response.

“It’s a negative that is reinforced 50 times an hour on network television from now until he’s no longer ill,” Rooney said.

U.S. Sen. Chris Coons (D., Del.), a top Biden ally, said this moment should be a “bracing reminder” for the entire country about the seriousness of the virus, if “the president of the United States, surrounded by people getting tested daily, still contracts it.”

And with the second debate scheduled for Oct. 15, Coons said the commission that runs the debates should consider taking them virtual. "It should make every candidate reconsider how they’re going to protect the public themselves and whether they do public events at all,” Coons said.

But Trump’s rallies are tough to replace, said Lee Snover, chairwoman of the Northampton County GOP. “Nothing can replace the local story, the local newspaper, that he cares about our area," she said. "It energizes the base.”

Snover said she had just told a top Trump campaign official in Pennsylvania on Thursday that the president “has got to get to Northampton County.” The county is one of three in the state that voted for President Barack Obama in 2012 before backing Trump in 2016.

“I thought he needed a trip to the Lehigh Valley in the next two weeks,” she said, adding Trump could still campaign there once he has recovered.

In the meantime, Snover said, she hopes the Trump campaign dispatches surrogates, like the president’s children, to travel the state while he’s quarantined at the White House. She said Trump could campaign virtually, too. “Get him back on the damn TV,” she said of the former reality television star. “Are we all forgetting where he came from?”

Former Gov. Ed Rendell, a Biden backer, said he hopes this moment changes people’s attitudes about the seriousness of the virus.

“I don’t think it changes the political dynamic in terms of who’s getting how many votes,” Rendell said. “I hope it changes the national dynamic, though. I hope this is the turning point that he can convince everyone that wearing masks is important, social distancing is important.”

Trump tested positive after attending a fun in Bedminster, N.J. New Jersey Gov. Phil Murphy has since urged anyone who attended to get tested. Biden had a virtual fundraiser in Philadelphia last week and another planned for Friday night with Rendell and longtime Democratic fundraisers David L. Cohen, Ken Jarin and Alan Kessler.

“You got to believe the campaigns are going to take a step back. Even Republican campaigns at this point," Kessler said. "Just because they’re presidential candidates doesn’t mean they’re somehow immune to what we all face. I think it dramatically affects the last five weeks of campaigning.”

Staff writers Allison Steele, William Bender, and Jessica Calefati contributed to this article.