In a recent interview, Mr. Trump offered a vainglorious pre-obituary of sorts for his candidacy, should he ever end it (for which he insists he has no plans).

“There’d be a major collapse of the race, and there’d be a major collapse of television ratings,” he said from his office in Trump Tower. “It would become a depression in television.”

Mr. Trump said that a presidential campaign without him would become so “boring” that he would struggle to pay any attention to it.

“I wouldn’t even be watching it probably, and neither would anybody else,” he said.