Steve Cortes, a senior adviser to Mr. Trump’s campaign, said on “Fox News Sunday” that the president and his associates had taken “tremendous precautions” to avoid the virus, even though Mr. Trump is rarely seen wearing a mask and has held large, and largely mask-free, events in violation of public health recommendations.
Even with President Trump still hospitalized with Covid-19 on Sunday, officials on his campaign continued to defend his flouting of public health guidelines and refused to acknowledge that it could have led to his infection and the infections of other Republicans.
Mr. Cortes outlined a false choice, suggesting that the alternative to holding large events without masks was to remain “hermetically sealed” in the White House. He added that the president had been “unwilling to completely sequester himself, to take no risk, because leaders take risks,” and went on to argue that Mr. Trump’s illness showed the futility of protective measures — many of which the president did not actually take.
Another Trump campaign aide, Jason Miller, made similarly misleading remarks on NBC’s “Meet the Press,” describing Mr. Trump as “the single most protected person on the entire planet” without mentioning the precautions the president has often rejected.
In a remarkable exchange with the Fox News host Chris Wallace, Mr. Cortes defended the refusal of Mr. Trump’s family members to wear masks at Tuesday’s debate, which Mr. Wallace moderated. Mr. Cortes insisted that masks had been unnecessary because the family tested negative before the debate — even though Mr. Trump and his wife, Melania, later tested positive, and even though health officials had explicitly mandated masks regardless of test results.
Health officials are clear that masks are crucial to controlling the virus. Dr. Robert R. Redfield, the director of the Centers for Disease Control and Prevention, told a Senate committee in September that they might be more important than even a vaccine.
CORTES: Chris, we believe that masks are very useful. The president has worn them on many occasions, including visiting the hospital where he is now a patient — when he was visiting as commander in chief, as a guest to visit soldiers there, he wore a mask. We believe in masks. We also believe in some element of individual choice. People were distanced and they had been tested.
WALLACE: Everybody was told to wear a mask. Why did the first family and the chief of staff feel that the rules for everybody else didn’t apply to them?
CORTES: Look, those chairs were not close together, and again, we also believe that —
WALLACE: They weren’t distanced and there were rules and there was no freedom of choice. They broke the rules. Why did they break the rules?
CORTES: Chris, the way you’re starting to harangue me now actually reminds me of what you did to the president during that debate on Tuesday night.
WALLACE: It doesn’t matter. They were close together, Steve, and the rules from the Cleveland Clinic were everybody wears a mask. Why didn’t they?
“I think too often he’s used the mask as a prop,” Mr. Miller said. “Masks are very important, but he could be 20, 30 feet away from the nearest person and still have the mask on. That’s not going to change anything that’s out there. But also, we’ve seen with Joe Biden — I mean, we can’t all just stay in our basement for the rest of our lives.”
On ABC’s “This Week,” Mr. Miller continued to mock Joseph R. Biden Jr. for wearing masks.
Vice President Mike Pence, who would be the most powerful man in the nation should President Trump become too ill to continue his duties, has been on the campaign trail despite having been in close contact with the president and being at high risk of having the virus himself.
Mr. Trump posted a video to Twitter on Saturday evening, offering his own account of his health. “I’m starting to feel good,” he said, adding “we’ll be seeing what happens over those next couple of days.”
Though Mr. Pence has tested negative each of the last three days, it is possible to test negative and still be infected early in the course of the virus.
“There is no way under the sun that Pence should be anywhere but in his home,” said Dr. Rochelle Walensky, an infectious disease expert at Harvard University. “He was sitting in a sea of people with Covid; there is no way he should go anywhere.”
And it puts Mr. Pence and anyone who came into contact with Mr. Trump on Tuesday squarely at risk. Chris Christie, the former governor of New Jersey, who helped the president at the White House with debate preparation from last Saturday through Tuesday, has tested positive.
Mr. Pence was last in contact with the president on Tuesday morning at the White House. He may have also been in close contact with several others who tested positive after having attended the White House event last Saturday to celebrate the nomination of Judge Amy Coney Barrett. Mr. Trump began feeling symptoms as early as Wednesday, and several studies have shown that people are most infectious from one to two days before showing symptoms to about two days after. This could mean that Mr. Trump was already highly infectious on Tuesday.
Mr. Biden has continued to campaign, traveling to Grand Rapids, Mich., on Friday, and holding a virtual town hall with a union on Saturday. He is usually seen wearing a mask at campaign events.
Former Vice President Joseph R. Biden Jr. is also at risk of being infected, experts say. Although he and Mr. Trump stood more than 12 feet apart at the debate, they were indoors. Studies have shown that indoors, the virus can travel farther than six feet, prompting experts to recommend that Mr. Biden also quarantine and get tested daily.
Mr. Pence’s team has said that he tested negative for the coronavirus on Friday, Saturday and Sunday. But tests for the virus can produce false negatives if used too early in the course of infection. The virus can take up to 14 days to show symptoms, which is why the Centers for Disease Control and Prevention recommends that anyone who has been in close contact with an infected person quarantine for 14 days.
Mr. Pence, meanwhile, has traveled to several states and participated in outdoor and indoor campaign events. On Wednesday, he attended a packed fund-raiser in Atlanta, and on Thursday spoke at two indoor events in Iowa. He did not wear a mask on either day; nor did most attendees.
He is scheduled to hold a rally at a police-equipment manufacturer in Arizona on Thursday.
Trump campaign officials said Sunday that Mr. Pence had no plans to curtail his public appearances. “He will be hitting the trail,” Jason Miller, the campaign’s senior adviser, told CNN. “And he’s going to have a very full, aggressive schedule.”
Officials with Joseph R. Biden Jr.’s campaign said on Sunday that Mr. Biden would continue to travel for campaign events even though he shared a debate stage with President Trump shortly before Mr. Trump tested positive for the coronavirus.
Donald McNeil Jr. contributed reporting.
Mr. Biden has tested negative, and his campaign said he was being tested before each trip, but tests are not always reliable in the early stages of an infection.
Based on the timing of Mr. Trump’s diagnosis, medical experts say it is likely that he was contagious during his debate with Mr. Biden on Tuesday, and Centers for Disease Control and Prevention guidelines call for 14 days of quarantine for anyone exposed to the virus.
But while six feet is a rule of thumb, it is not a definitive line beyond which there is no risk of exposure. Researchers have established that the virus can travel farther than six feet, particularly indoors.
Symone Sanders, a senior adviser to Mr. Biden, emphasized on CNN that he and members of his campaign staff were wearing masks, holding events outdoors, enforcing social distancing and taking other precautions, and said that because he had been “well over six feet away” from Mr. Trump, “Vice President Biden was not exposed.”
“The most responsible thing to do in this situation is to just wait and see,” Dr. Morrison said. “And in the meantime, treat yourself as if you are infected.”
Juliet Morrison, a virologist at the University of California, Riverside, said that given his proximity to Mr. Trump at a time when the president was probably infectious, Mr. Biden should quarantine.
“We hope that they’re going to put in place every adjustment necessary to ensure that it’s fully safe,” Ms. Bedingfield said on ABC, referring to the commission organizing the debates. “And obviously we send President Trump our best. We hope that he is well and able to debate. If he is, Joe Biden will certainly be there.”
Ms. Sanders and Kate Bedingfield, Mr. Biden’s deputy campaign manager, both said they hoped the next debate, scheduled for Oct. 15 in Miami, could be held safely.
An NBC News/Wall Street Journal poll, conducted on Wednesday and Thursday after the debate, found that 53 percent of registered voters planned to vote for Mr. Biden and 39 percent for Mr. Trump, with a margin of error of plus or minus 3.5 percentage points. The 14-point lead is the largest Mr. Biden has had in any NBC/Wall Street Journal poll this year.
Joseph R. Biden Jr. leads President Trump by double digits in two national polls released on Sunday, one of which was conducted after the presidential debate but before Mr. Trump announced that he had the coronavirus, and one of which was conducted after the announcement.
The second poll, conducted by Reuters and Ipsos on Friday and Saturday, after the president said he had the virus, showed Mr. Biden with a 10-point lead over Mr. Trump, 51 percent to 41 percent. The margin of error was plus or minus five percentage points.
Mr. Biden benefited from huge leads among older voters (62 percent to 35 percent) and suburban women (58 percent to 33 percent). In 2016, most older voters voted for Mr. Trump over Hillary Clinton, exit polls found.
In a third poll, by ABC News and Ipsos, 72 percent of respondents said Mr. Trump had not taken the risk of contracting the virus seriously enough, and the same number said he had not taken “the appropriate precautions when it came to his personal health.” That poll did not ask about the election.
Sixty-five percent of respondents in the Reuters/Ipsos poll agreed with the statement that “if Mr. Trump had taken coronavirus more seriously, he probably would not have been infected.” That included roughly nine in 10 registered Democrats and about half of registered Republicans.
Notably, since the announcement that Mr. Trump was infected, Republicans and independents appear to have become much more concerned that they or someone they know will contract the virus.
Mr. Trump has flouted public health guidelines for months, continuing to hold large rallies — including some indoors, where the risk of transmission is higher — and almost never wearing a mask. At the presidential debate last week, during which he may already have been infected, he mocked Mr. Biden for wearing a mask.
President Trump’s hospitalization has plunged an already volatile race into extraordinary uncertainty, sidelining the president indefinitely with a month until Election Day and making the pandemic a more urgent and delicate issue for Joseph R. Biden Jr.
Seventy percent of Republicans in the ABC News poll said they were concerned, up from 52 percent just two weeks ago, and 82 percent of independents said they were concerned, up from 69 percent. Among Democrats, the number was unchanged at 86 percent.
“I think I’ll be back soon,” Mr. Trump, seated at a dark-wood table and wearing a jacket but no tie, said in a video posted on Twitter. “And I look forward to finishing up the campaign the way it was started and the way we’ve been doing.”
On Saturday, Mr. Trump remained at Walter Reed National Military Medical Center, where he sought to send a reassuring message that he was “starting to feel good.”
Mr. Trump acknowledged that the next few days could be “the real test” in determining his medical condition.
But given the uncertain course of the virus, it could be weeks before Mr. Trump can return to the campaign. His aides canceled rallies that were to be held in Florida on Friday and Wisconsin on Saturday and said they would consider future events on a “case-by-case basis.”
“I’m in a little bit of a spot here because I don’t want to be attacking the president and the first lady now,” Mr. Biden said at a virtual event on Saturday with members of the Amalgamated Transit Union, adding that he had prayed for the couple’s quick recovery.
Mr. Biden has for months sought to make the race a referendum on Mr. Trump’s stewardship of the pandemic, but that task has become more sensitive in light of Mr. Trump’s hospitalization.
The Trump campaign is not changing its advertising or messaging, even with the candidate in the hospital. The political operation is not bereft of leaders; the campaign manager is still helping run things from afar after testing positive for the virus. Advisers are not showing any evidence of worry, despite public polls showing President Trump still behind in key states he won in 2016.
Still, Mr. Biden criticized the Trump administration for not requiring transit riders to wear masks and for not doing more to get personal protective equipment for workers. “I promise you, I’m going to get you all the P.P.E. that’s necessary,” Mr. Biden said.
At 4 p.m. on Saturday, Vice President Mike Pence held a call with the Trump-Pence re-election staff nationwide, trying to rally the troops and lay out the plans for the coming weeks.
On the first weekend of the new Trump political reality, the overarching signals were about continuity and resolve, even though the landscape was one of change: rallies canceled in Wisconsin, fund-raising reworked without the incumbent candidate and campaign operations adjusting on the fly.
“‘Make America Great Again’ isn’t just a slogan; it’s our mission,” Mr. Pence said on the call.
Despite the almost unthinkable circumstances for a campaign whose fund-raising, events and political pitches have all been driven by the president himself, Mr. Pence tried to signal that the campaign was trying to proceed as if little has changed.
“The leader of the campaign may be off the field for now,” he said. “But people are voting right now. The blocking and tackling of knocking doors, making phone calls and getting people to the polls must continue. They can’t worry about what they can’t control and must work relentlessly at what they can.”
Matt Gorman, a Republican strategist, said the campaign’s only option was to plow forward.
Justin Clark, the deputy campaign manager, is filling in at the headquarters in Virginia for the campaign manager, Bill Stepien. But Mr. Stepien is working remotely from home, officials said, and telling other staff members that he feels fine. He participated on the call with staff members across the country on Saturday. (Jared Kushner, the president’s son-in-law and a top political adviser, has not needed to play a greater role in the candidate’s absence.)
To compensate for Mr. Trump’s absence, the campaign is trying to deploy as many Trump family members, who are popular with the president’s supporters, as is possible while the president is off the trail.
Senator Patrick J. Toomey, a Pennsylvania Republican, will not seek re-election in 2022, vacating a battleground-state race more than two years before he leaves office.
The campaign hopes to be able to tell a story of what one adviser described as “resolve,” with the president — and several top aides — overcoming a virus that Mr. Trump has for months played down.
Mr. Toomey’s spokesman, Steve Kelly, declined to comment on his decision but said that Mr. Toomey would make an announce Monday morning.
Mr. Toomey, 58, last week informed Senator Mitch McConnell, the majority leader, of his decision not to seek a third term, according to a person familiar with their conversation. The Philadelphia Inquirer, which broke the news of Mr. Toomey’s decision, reported that he would also not run for governor of Pennsylvania in 2022.
In 2013, he partnered with Senator Joe Manchin, a West Virginia Democrat, to put forward background-check legislation after the Sandy Hook school massacre in Connecticut. The bill failed, and the Senate has not considered significant gun control legislation since.
A fiscal and social conservative who was president of the hard-right Club for Growth before his 2010 Senate campaign, Mr. Toomey carved out a niche as a rare Republican willing to entertain gun control proposals like expanded background checks.
“It takes away our best candidate,” Rob Gleason, a former chairman of the Pennsylvania Republican Party, said of Mr. Toomey’s decision. “It throws it pretty wide open for sure.”
Mr. Toomey’s decision to not seek re-election complicates what was already shaping up to be a tough 2022 map for Republicans. The timing of his announcement, one month before the 2020 general election that has consumed political attention in Pennsylvania, came a surprise.
Democrats will be defending far fewer likely competitive seats — in Colorado, New Hampshire and Nevada.
Along with the now-open seat in Pennsylvania, the party will be defending seats likely to be competitive in Florida, Iowa, North Carolina, Ohio and Wisconsin — all battlegrounds in the current presidential campaign.
Four days after a debate in which President Trump might have exposed Joseph R. Biden Jr. to the coronavirus, South Carolina’s Democratic Senate candidate, Jaime Harrison, brought a plexiglass divider to his debate with Senator Lindsey Graham.
The winner of Arizona’s 2020 Senate race to complete the remainder of Senator John McCain’s term, between Senator Martha McSally, a Republican, and former astronaut Mark Kelly, a Democrat, will also be up for re-election to a full six-year term in 2022.
“Tonight I am taking this seriously,” he said. “That’s why I put this plexiglass up. Because it’s not just about me — it’s about the people in my life that I have to take care of as well. My two boys, my wife, my grandmother.”
Mr. Harrison mentioned the divider directly during the debate on Saturday, saying he needed to protect himself for the sake of his family.
The race between Mr. Graham and Mr. Harrison, in a state that voted for Mr. Trump by more than 14 percentage points, has been unexpectedly competitive, with multiple polls showing the candidates tied or nearly tied.
Mr. Graham, the chairman of the Senate Judiciary Committee, may have been exposed to the virus earlier in the week by Senator Mike Lee of Utah, who serves on the committee and has tested positive. While Mr. Graham has tested negative, it can take several days for an infection to become detectable, and the Centers for Disease Control and Prevention instructs people to quarantine for 14 days after exposure.
Joe Biden leads Donald Trump in Florida and Pennsylvania. Both states are crucial to Mr. Trump’s re-election chances.
|2016 Election Result||NYT/Siena
By overwhelming margins, voters in Pennsylvania and Florida were turned off by President Trump’s conduct in the first general election debate, according to New York Times/Siena College surveys, as Joseph R. Biden Jr. maintained a lead in the two largest battleground states.
Based on New York Times/Siena College polls of 710 likely voters in Florida from Sept. 30 to Oct. 1 and 706 likely voters in Pennsylvania from Sept. 30 to Oct. 2.
The surveys began Wednesday, before the early Friday announcement that Mr. Trump had contracted the coronavirus. There was modest evidence of a shift in favor of Mr. Biden in interviews on Friday, including in Arizona where a Times/Siena survey is in progress, after controlling for the demographic and political characteristics of the respondents.
Over all, Mr. Biden led by seven percentage points, 49 percent to 42 percent, among likely voters in Pennsylvania. He led by a similar margin, 47-42, among likely voters in Florida.
The debates long loomed as one of the president’s best opportunities to reshape the race in his favor. He has trailed in Pennsylvania and Florida from the outset of the campaign, and he does not have many credible paths to the presidency without winning at least one of the two — and probably both.
One day of interviews is not enough to evaluate the consequences of a major political development, and it may be several days or longer before even the initial effects of Mr. Trump’s diagnosis can be ascertained by pollsters.
But while Mr. Trump failed to capitalize on a rare opportunity to claw back into the race, the findings suggest that the debate did not shift the contest decisively in Mr. Biden’s direction, either. The results were close to the average of pre-debate surveys in both states, another reflection of the unusually stable polling results ahead of the election. In Pennsylvania, the race was even somewhat closer than it was in a Times/Siena poll conducted before the debate, which found Mr. Biden ahead by nine percentage points.
Instead, a mere 22 percent of likely voters across the two pivotal states said Mr. Trump won the debate Tuesday. It leaves the president at a significant and even daunting disadvantage with a month until Election Day.
President Trump’s bombshell announcement early Friday morning that he and the first lady had tested positive for the coronavirus has set off a frenzy in the White House and beyond as politicians and operatives who have interacted with Mr. Trump in recent days have raced to get their own tests and, in some cases, report the results.
The lack of additional gains by Mr. Biden after the first debate might have been all but inevitable in a deeply polarized country. But it might also suggest that Mr. Biden, like the president, failed to capitalize on opportunities of his own.
It can take several days after exposure for the virus to reach levels that are detectable by a test. People show symptoms on average around five days after exposure, but as late as 14 days.
Here is a quick look at the people in Mr. Trump’s orbit and beyond who have spoken publicly about their health and the virus, taken from official statements, and announcements made on social media and by spokespersons.
Who has tested positive:
Hope Hicks, one of Mr. Trump’s most senior advisers
Ronna McDaniel, the chairwoman of the Republican National Committee
Kellyanne Conway, the former top White House adviser, who attended Judge Amy Coney Barrett’s Supreme Court nomination ceremony at the White House on Sept. 26
Bill Stepien, President Trump’s campaign manager
Senator Thom Tillis of North Carolina, who participated in a debate against his Democratic challenger on Thursday
Senator Mike Lee of Utah, who met with Judge Barrett on Tuesday
Senator Ron Johnson of Wisconsin, who did not attend Judge Barrett’s ceremony last week
Rev. John I. Jenkins, the president of the University of Notre Dame, who also attended the ceremony for Judge Barrett last week
Nick Luna, a White House aide
Chris Christie, the former governor of New Jersey
Steven Mnuchin, the Treasury secretary
Who has tested negative:
Mike Pompeo, the secretary of state
Mark Meadows, the White House chief of staff
William P. Barr, the attorney general
Jared Kushner, Mr. Trump’s son-in-law and senior adviser
Dan Scavino, the White House deputy chief of staff
Donald Trump Jr., Mr. Trump’s son
Ivanka Trump, Mr. Trump’s daughter
Eric Trump, Mr. Trump’s son
Barron Trump, Mr. Trump’s son
Tom Perez, the chairman of the Democratic National Committee
Lara Trump, Eric Trump’s wife
Senator Ben Sasse, Republican of Nebraska and a member of the Judiciary Committee. He attended Judge Barrett’s ceremony.
Betsy DeVos, the education secretary
Mitch McConnell, the Senate majority leader, announced on Saturday that the Senate would not meet as planned next week after three senators tested positive for the virus, but indicated that Republicans would press ahead to confirm Judge Amy Coney Barrett to the Supreme Court without delay.
Senator Josh Hawley, Republican of Missouri and a member of the Judiciary Committee. He attended Judge Barrett’s ceremony.
The announcement comes after three members of Mr. McConnell’s conference, two of them on the Judiciary Committee, have tested positive for the coronavirus in the past 24 hours. Others, like Senator James Lankford of Oklahoma, have tested negative but have gone into quarantine.
“The Senate’s floor schedule will not interrupt the thorough, fair and historically supported confirmation process previously laid out,” Mr. McConnell, Republican of Kentucky, said in a statement, adding that the Senate Judiciary Committee had “successfully” met with senators appearing both in person and virtually since May.
Unlike Senators Thom Tillis of North Carolina and Mike Lee of Utah, who tested positive on Friday, Mr. Johnson does not sit on the Senate Judiciary Committee. But his positive test result adds new complications to the timing of Judge Barrett’s confirmation.
Ron Johnson of Wisconsin, the third Republican senator to test positive for the coronavirus this week, was exposed to an individual earlier in the week who tested positive for the virus, according to his office, which said the senator was “not experiencing symptoms.” He did not attend President Trump’s nomination ceremony for Judge Barrett at the Rose Garden on Saturday.
“If it’s too dangerous to have the Senate in session, it is also too dangerous for committee hearings to continue,” Senator Chuck Schumer of New York, the Democratic leader, said in a statement. “Leader McConnell and Chairman Graham’s monomaniacal drive to confirm Judge Barrett at all costs needlessly threatens the health and safety of senators, staff and all those who work in the Capitol complex.”
Top Senate Democrats demanded that Republicans slow their plans for confirming Judge Barrett.
But leading Republicans have said they planned to continue “full steam ahead” to confirm Judge Barrett before Election Day.
The Sept. 26 Rose Garden ceremony for Judge Barrett was most likely not a “super-spreader” event, because it was outdoors. However, many top Republicans attended without masks or social distancing, raising concerns that others might have contracted the virus but had not yet been diagnosed. And someone who was infected and did not have symptoms could have transmitted the virus to others during indoor discussions inside the White House.
And in an interview on Friday, Mr. McConnell suggested that the virus’s spread through Republican circles could mean that more lawmakers would participate in the hearings virtually. “This sort of underscores the need to do that,” he said.
Senator Lindsey Graham of South Carolina, the Judiciary Committee chairman, said on Friday that his panel would begin four days of public hearings on Judge Barrett’s nomination on Oct. 12, as scheduled. Mr. Tillis and Mr. Lee said they would isolate for 10 days, which would enable them to emerge in time for the hearings.
Republicans hold a narrow majority in the Senate, meaning they can only afford to lose three votes in their push to confirm her. Two Republicans, Senators Lisa Murkowski of Alaska and Susan Collins of Maine have said they would not confirm a nominee before the election.
But Democrats said that virtual hearings on such a consequential matter would be unacceptable.