Of course, since the candidate hadn’t been doing anything other than on his own terms, the decision wasn’t a political one any more than Mr. Trump’s is a political campaign. It was a decision designed to make sure he continues to be an attentionmonger rather than another pol. Mr. Bannon, a provocateur at Breitbart, has never run a campaign, but he knows a lot about how to get media attention.

Nevertheless, that attention, as we are seeing, won’t necessarily help Mr. Trump win the election, which isn’t to say that there might not be a method to his narcissism. Winning means different things to different candidates. It doesn’t always mean winning the vote.

Mike Huckabee used the attention he got in his losing campaign to land a gig on the Fox News Channel. Sarah Palin used hers to get a reality show and enormous speaking fees. Ben Carson used his to sell books. Losers at the ballot box, they were all winners in a manner of speaking.

Television shows, books and speeches would be small potatoes for Mr. Trump, whose dictum, according to his daughter Ivanka, is, “If you’re going to be thinking anyway, you might as well think big.” And that is where attention meets victory.

If you think of his campaign as a real-estate negotiation, the man who coined the term “art of the deal” has taken a huge edifice, plastered his name all over it without investing much in it, and is very likely to abandon it as a troubled asset once the election is over and its value is diminished, leaving others holding the bag, just as he reportedly did during his serial bankruptcies. Only, in this case, the edifice is the Republican Party. It is Mr. Trump’s biggest deal ever.

And Mr. Trump leaves not only with 18 months of headlines and cheering crowds, but with an even bigger brand. Sarah Ellison of Vanity Fair and Brian Stelter of CNN have speculated that Mr. Trump may want to use his new notoriety to build a media empire. His alliance with Mr. Bannon may help him do that. So may his reported linkup with Roger Ailes for campaign advice.