On Thursday, Donald Trump signed a loyalty pledge to the Republican Party, stipulating that he would support whoever becomes the GOP's presidential nominee and foreclose the option of mounting an independent or write-in or third-party candidacy. The purpose of the pledge was to bring Trump to heel. By announcing his decision publicly, and holding the signed pledge up to a thousand cameras, Trump gave the Republican party readymade and provocative attack ad material: In the event that he shirks the agreement, and mounts an independent candidacy at some point, Republicans can air footage that proves Trump broke his word.

There may be some solace in that, but the fact that he was willing to sign the pledge at all should alarm Republicans more than it soothes them. Trump wasn’t communicating to the party that its knock against him for threatening an independent run has been effective. To the contrary, it's that he doesn’t think the threat is necessary anymore—that he’s now genuinely well-positioned to win the primary, rather than an insurgent threat who can be neutralized by party heavyweights.

This isn’t just a matter of polling—though the polling is consistent with it—but of the way Trump speaks about the pledge itself. He clearly doesn’t see it as an inviolable agreement, but rather as a way to keep the Republican Party from organizing to sabotage his candidacy.

“I really got nothing,” Trump said at a Thursday press conference in New York, speaking about his meeting with Republican National Committee Chairman Reince Priebus. “Absolutely nothing other than the assurance that I would be treated fairly…. I have no intention of changing my mind.”

He got nothing, in other words, aside from an all-purpose and unchallengeable exception, which will force party officials to constantly police one another to make sure they don’t give Trump the excuse he’ll need to launch an independent campaign.