That's one reason why he's never really run before. Another likely reason is that he was loath to release detailed financial documents, perhaps until he realized that they weren't as detailed as he might have feared. A third reason was probably that running for president is a gigantic pain, involving lots of flying to tiny places, shaking hands with a bunch of nobodies, and having to watch yourself trail classless dorks in the polls.
But that's not how this campaign has gone. Trump's done a bit of traveling, heading to Arizona and South Carolina and, now, to Texas. He's done some press conferences, but seems mostly content sitting in New York City and phoning in to various national TV interviews. That's been enough, thanks to his having stumbled onto a successful anti-immigration campaign platform. He mostly stays home, people cheer, his poll numbers rise. It's the dream campaign.
At some point, the Republican establishment, slow to figure out how to kneecap the Tea Party movement, will figure out how to kneecap him (or at least give him some blisters). At some point, Trump's poll numbers are going to go down. At that point Trump will have to choose: Slog it out, or bail?
The most enticing option will be to bail. Trump's instinct toward self-preservation -- the instinct that inspires him to belittle newspapers and opponents -- demands that he not admit he's leaving the race because it's become difficult.
Enter the third-party bid.
He's sort of toyed with this before, but in an interview with The Hill published Thursday, he was more direct. "The [Republican National Committee] has not been supportive," he said. Asked if he'd run outside the party, he replied that "so many people want me to, if I don’t win" -- but that "I'll have to see how I’m being treated by the Republicans."
Here's one possibility for what might happen. Trump's poll numbers start to slip, or other candidates start to consolidate votes and move ahead of him. That's the warning sign that Trump will be looking for. He'll rail more furiously against the party establishment, saying that the party doesn't reflect him or respect his base. He'll blame them or other outside forces for the polling, and announce that he will no longer seek the party's endorsement, and that he plans, instead, to run as an independent candidate. It won't be his fault, see. He'll have been forced out because he has to follow his principles.
Time will pass. He'll be included in polls (as has already happened) and will poll moderately well. He'll probably hold on to much of the support that he's seen so far, for a while.
Then, eventually, he'll come back into the fold. Some candidate or the eventual Republican nominee will reach out to him, pledge to move his issues to the forefront, and get Trump's support. (This is known as "pulling a Romney.") Trump will be told that he can be kingmaker, can be the guy who won the election for the right. That will be hard for Trump to resist.
And with that, the insurrection will be quelled. Trump will have gotten what he wanted, and be able to exit without having to admit that maybe, just this once, he didn't get what he wanted.
Or maybe he'll see his poll numbers keep going up and up until he's the next president. I've been wrong before.