How, then, could Mr. Trump come back? For one thing, Mr. Adams recommends he make a show of empathy, his apparent lack of which is central to his detractors’ fear of him. I note that he missed an obvious opportunity when he went on the attack against Khizr Khan—the Muslim father of a fallen Army captain, whose denunciation of Mr. Trump electrified the Democratic Convention—without acknowledging the family’s loss or the son’s sacrifice.

Mr. Adams grants the point and observes: “That’s where we have to wonder if there’s some self-sabotage going on, because the right answer was available to him and to everybody. Almost anybody could have gotten that right. It bordered on intentional. I wouldn’t say it was intentional, but when you watch it, you have to scratch your head and say: Of all the things you could have said, maybe a little softness on the fallen soldier would have gone a long way.”

The debates could work in Mr. Trump’s favor, for Mr. Adams believes he is faster on his feet than Mrs. Clinton: “He can do it on demand. She probably still has to be coached—‘say this, don’t say that.’ In a debate, if things go not as expected and not as they prepared, Trump’s got an advantage, because he’s just going to somewhat instinctively go to a simple, visual, provocative thing that benefits his side. She probably won’t. She will probably default to some data, some reason, some experience kind of argument, which would be less effective.”

The latter type of argument, ironically, could be effective for Mr. Trump: “The expectations are so low in terms of what he might have mastered in policy and facts and truth that if he simply showed up a little bit practiced, and a little bit studied, so that if she brings up an issue and he throws some facts at her that pass the fact checkers—for the first time—he doesn’t have to be as good as her.”