Advisers had for days been gently suggesting that the president reconsider his approach, arguing that promoting mask-wearing was patriotic, and Mr. Trump signaled he was ready for a change, the people said.

“It just was a mismatch with the reality on the ground,” said a senior administration official of the White House’s previous lack of high-level, public focus on the issue…

“The president has decided that he’s losing more of his base than he’s gaining with his approach to Covid,” said Republican donor and energy-company executive Dan Eberhart. “He’s seeing his numbers just like everyone else, and he is realizing that he has to change course.”…

A person in close contact with the White House said there was agreement among White House and campaign aides that the president’s insistence that the economy should reopen was out of step with the concerns of many Americans, who wanted a focus on health and safety.

“Everybody recognized,” the person said, “we’ve gotta pivot.”