“It just destroys him to seem to be abandoning his base on any issue,” said Douglas Brinkley, the presidential historian. “When he originally said he distanced himself from the chant at the rally, one could have guessed he would go back and embrace the people who cheered ‘Send her back!’ Contrite is not in his playbook.”

But even some critics of Mr. Trump said that the walkback of the walkback was not necessarily damaging to him. “I wish I could say it was foolish, but what have the actual consequences been in the real world or in Republican support of him sticking to his guns?” said William Kristol, the conservative columnist and prominent Trump opponent. “Being the tough, unapologetic guy, it keeps his brand stronger even if he takes a little bit of a hit.”

Mr. Trump continued his condemnation of Ms. Omar on Friday, claiming that she had “called our country and our people garbage.” It was not clear what remarks she made that he was referring to.

That attack continued his racially charged fight with Ms. Omar and three of her fellow Democratic congresswomen of color — Representatives Alexandria Ocasio-Cortez of New York, Ayanna S. Pressley of Massachusetts and Rashida Tlaib of Michigan — into a sixth day.

Administration officials and campaign aides have rejected comparisons between Mr. Trump’s goading of elected women of color to “go back” to where they came from and what happened in Charlottesville. One was a deadly incident, they said, the other was a political fight.

But campaign aides have acknowledged that Mr. Trump’s tweets on Sunday — in which he used an age-old racist adage in telling the congresswomen to “go back and help fix the totally broken and crime infested places from which they came” — were unexpected, used loaded and unhelpful language, and any political strategy attached to them was reverse-engineered after the fact.

The president claimed his attacks were not politically motivated. “I don’t know if it’s good or bad politically; I don’t care,” he said. “I can tell you this, you can’t talk that way about our country. Not when I’m the president.”