The next presidential debate fell into serious jeopardy on Thursday after President Trump said he would refuse to participate in a virtual matchup and Joseph R. Biden Jr. pledged to hold an alternative town hall with voters on the night of the scheduled event.
The extraordinary developments came after Mr. Trump rejected plans by the Commission on Presidential Debates to have the candidates square off remotely from separate locations on Oct. 15, rather than onstage in Miami, citing health concerns about the coronavirus.
Mr. Trump, whose recent contraction of the coronavirus was a significant impetus for the commission to modify its plans, immediately dismissed the idea of a virtual debate as “ridiculous” and accused the debate commission without evidence of seeking to protect his Democratic opponent.
“No, I’m not going to waste my time on a virtual debate,” Mr. Trump told the Fox Business anchor Maria Bartiromo. “That’s not what debating is all about. You sit behind a computer and do a debate — it’s ridiculous.”
The Biden campaign initially said it would welcome the virtual debate on Oct. 15, which was to follow a town-hall-style format with questions from Florida voters. But after Mr. Trump’s objections, aides to Mr. Biden said that the Democratic presidential nominee would “find an appropriate place to take questions from voters directly” that evening.
By lunchtime, the campaigns were embroiled in a back-and-forth over when, where, and on what terms the two candidates might meet again before Election Day.
Mr. Trump’s campaign manager, Bill Stepien, perhaps sensing some political disadvantage to skipping the remaining debates, said that the president would agree to another matchup if it were delayed by a week and held in-person on Oct. 22 — a move that would potentially give Mr. Trump more time to recover from the coronavirus. Mr. Stepien also proposed an additional debate on a new date, Oct. 29, which has not previously been considered by the commission.
Kate Bedingfield, a Biden deputy campaign manager, quickly rejected the idea. “Donald Trump doesn’t make the debate schedule; the debate commission does,” she said in a statement. “Trump chose today to pull out of the Oct. 15 debate. Trump’s erratic behavior does not allow him to rewrite the calendar, and pick new dates of his choosing.”
Both campaigns appeared open to a meeting on Oct. 22, the original date of the third presidential debate. But what format that event might take — and whether Mr. Trump would agree to appear virtually — was unclear.
The debate commission, which did not respond to repeated requests for comment, did not consult with the Biden and Trump campaigns before announcing the virtual format early on Thursday. The decision came after members of the commission’s production team objected to the safety risks of staging another in-person event at an indoor venue, according to a person familiar with its deliberations.
The contretemps on Thursday may pose the most significant test to the debate commission’s legitimacy since the group, a nonpartisan body, was founded in 1987.
There is no law that presidential candidates must take part in debates. Traditions and norms govern the practice, and like many political institutions in recent years, the commission’s board now faces its own Trumpian stress test.
Newton N. Minow, 94, a member of the commission who has been involved in every general-election debate since 1960, said on Thursday that the day’s developments amounted to “a big loss to the democratic process.”
“American voters are the losers — deprived of the opportunity to see, hear and evaluate presidential candidates through today’s technology,” Mr. Minow, who was appointed by John F. Kennedy in 1961 to chair the Federal Communications Commission, wrote in an email.
Directors of the debate commission include former senators, business luminaries, and the Rev. John I. Jenkins, the president of the University of Notre Dame who tested positive for the coronavirus last week.
The commission was already under pressure to reform its safety protocols after last week’s debate in Cleveland, where Mr. Trump’s family members and aides declined to wear masks in the debate hall, flouting regulations set by the organizers. Mr. Biden’s aides had also expressed concern about their candidate’s potential exposure to a president who could still be infectious.
Mr. Stepien, the president’s campaign manager, had initially issued a blistering attack on Thursday against the commission, calling its members “swamp monsters” and describing the move to a virtual debate as “pathetic.”
“The safety of all involved can easily be achieved without canceling a chance for voters to see both candidates go head-to-head,” Mr. Stepien said in a statement. “We’ll pass on this sad excuse to bail out Joe Biden and do a rally instead.” He also claimed that Mr. Trump “will have posted multiple negative tests prior to the debate,” although White House officials have repeatedly declined to give details about Mr. Trump’s current health status.
The president has not yet tested negative for the virus.
Mr. Trump, in the Fox Business interview, said he learned of the change to a virtual format on Thursday. But there were indications that people in the president’s circle were aware on Wednesday of the debate commission’s thinking about a virtual debate.
The president also sought repeatedly to undermine the integrity of the debate commission. He accused the scheduled moderator of the next debate, Steve Scully of C-SPAN, of being a “never Trumper,” without offering evidence for his claim. He said the moderator of the first debate, Chris Wallace of Fox News, “was a disaster” who favored Mr. Biden. And he said the commission’s plan for a remote matchup was about “trying to protect Biden.”
In fact, a presidential debate with candidates in different locations is not unprecedented.
In 1960, the third debate between John F. Kennedy and Richard M. Nixon was held remotely. Kennedy debated from a television studio in New York; Nixon appeared from Los Angeles, with the men filmed on a pair of identical sets. The moderator of that debate, Bill Shadel of ABC News, conducted the proceedings from a third studio in Chicago.
How to safely stage a pair of indoor, in-person debates between Mr. Biden and Mr. Trump, who tested positive for the coronavirus last week and spent three days at the Walter Reed National Military Medical Center, has been the subject of intense conversations among board members of the debate commission in recent days.
Aides to Mr. Trump had privately discussed the notion of debates held outdoors, but people familiar with the commission’s deliberations said the Trump campaign had never formally proposed that idea.
Both candidates have previously said they planned to participate in the Miami debate, with Mr. Trump insisting that he was “looking forward” to attending the event, despite the uncertainty over his health.
Mr. Biden has said he would defer to the debate commission and its health adviser, the Cleveland Clinic, to ensure a safe physical environment for the audience and participants. His aides have said the onus is on Mr. Trump to demonstrate that he would not be contagious onstage.
The debate commission did not address the third debate in its statement on Thursday. That matchup is scheduled to be held at Belmont University in Nashville on Oct. 22, with Kristen Welker of NBC News as the moderator.
The vice-presidential debate took place as planned on Wednesday in Salt Lake City, with Senator Kamala Harris of California and Vice President Mike Pence debating in person — albeit with plexiglass dividers between them.
Patricia Mazzei contributed reporting.