Before the debate comes the pre-debate. And in 2016, the pre-debate — titillating the politerati and network executives alike — goes something like this:

Will Donald J. Trump actually attend all three presidential debates, or will he walk off the stage Monday night after his first face-off with Hillary Clinton and, essentially, drop the mike?

For all its self-seriousness, Washington is naturally given to lighthearted guessing games: Will the Redskins ever be good again? How come everyone delights in posting green room selfies on Twitter and Instagram? And just why do young congressional aides still insist on wearing pleated khakis and boat shoes?

But even so, Mr. Trump, from his very first flirtation with politics (Will he actually run?) to the early days of his then-quixotic bid (Does he really have a shot?) to his ascension to the Republican nomination (Can he be stopped?), has displayed a showman’s knack for keeping audiences of all kinds raptly curious about his next act.