Friday was a day of “hibernation,” as one Biden adviser put it, an approach designed to allow the news cycle to burn on its own fuel.

Campaign advisers said that the public would come to its own conclusion that the president’s failure to protect the nation or take the pandemic seriously enough had come back to haunt him, and that his mockery of Biden for wearing masks and being cloistered “in his basement” was now freighted with an irony that could cost Trump a second term.

Their bottom line was this: on Friday, with just 32 days until Election Day, Biden was on the campaign trail in Michigan. And Trump, along with First Lady Melania, were in quarantine.

“Karma’s hell,” said one Biden donor, Dick Harpootlian, a South Carolina lawmaker. “Biden’s been right all along — there’s no joy in being right and you don’t want anyone to get ill, nobody’s getting smug about this. But it is four weeks before the election and Trump has taken himself off the playing field, which he brought on by himself.”