Mr. Trump’s typical name-calling can be recast to receptive audiences as mere “counterpunching.” His impeachment was explained away as the dastardly opus of overreaching Democrats. It is more difficult to insist that the man floating disinfectant injection knows what he’s doing.

The reaction has so rattled the president’s allies and advisers that he was compelled over the weekend to remove himself from the pandemic briefings entirely, at least temporarily accepting two fates he loathes: giving in to advice (from Republicans who said the appearances did far more harm than good to his political standing) and surrendering the mass viewership he relishes.

Some at the White House have expressed frustration that the issue has lingered. “It bothers me that this is still in the news cycle,” Dr. Deborah Birx, the coronavirus response coordinator, told CNN on Sunday, adding, “I worry that we don’t get the information to the American people that they need, when we continue to bring up something that was from Thursday night.”

Gov. Larry Hogan of Maryland, a Republican who has been willing to speak skeptically about Mr. Trump’s virus leadership, said on ABC’s “This Week” on Sunday that it “does send a wrong message” when misinformation spreads from a public official or “you just say something that pops in your head.” Asked to explain the president’s words, Mr. Hogan said, “You know, I can’t really explain it.”