“WHEN a man knows he is to be hanged,” Samuel Johnson once said, “it concentrates his mind wonderfully.”

Unless, of course, that man is Donald Trump.

Out of the nine presidential campaigns I’ve covered, I’ve never seen anything as absurd as the motley crew of Trump advisers agonizing over how to delicately, in soothing tones, tiptoe up to the proudly uninformed megalomaniac and broach the topic of more rigorous debate prep. Or, even more hilariously, trick him into practicing for the second contest so he doesn’t repeat his oblivious shame spiral.

In a country roiling with fears about terrorism, race relations and economic inequality, Trump managed to get fixated on the fact that a former Miss Universe gained a few pounds — and to gnaw on that issue for a week after leaving Hofstra, while mainlining bacon cheeseburgers. And this weekend, Trump was ensnared in another sensational story about the lascivious way he talks about women.

The denizens of Trumpworld — and furious and flummoxed Republicans — are dealing with a highchair king who gets huffy when he sees his advisers and allies acknowledging the obvious on TV: that he struggled in the first debate and that he should cease the self-immolating, misogynistic 3 a.m. tweets.