In addition to public surveys showing him losing decisively to Joseph R. Biden Jr. in a number of battleground states, private Republican polls in recent weeks show the president struggling even in conservative states, leading Mr. Biden by less than five points in Montana and trailing him in Georgia and even Kansas, according to G.O.P. officials who have seen the data…

The most visible example is Mr. Trump’s refusal to promote mask-wearing to fight the virus, which poses perhaps the most dire threat to his re-election. Several advisers have privately urged him to do so, to little avail.

“What I find hard to understand is that in order for the president to get re-elected, he’s going to want to see a really strong economy,” Senator Mitt Romney said, adding that a recovery can’t happen without slowing the spread of the virus, which includes wearing masks. “So I would think the president would be on the air hammering his base to get the economy back and win the election.”…

The president has resisted appeals from some advisers to start an onslaught of television advertising against Mr. Biden. Several people in touch with Mr. Trump and his campaign said the president strongly preferred seeing positive ads about his own accomplishments to negative ones about Mr. Biden. And he has told people he believes the race won’t be decided until October, as it was last time.