I'm a little surprised that Trump would do this at this point in the campaign, he's probably thinking he's got a legitimate shot and wants to trashcan any targeting opportunities against him prior to the next debate. It's not going to guarantee him what he might consider fair treatment going forward. But it's good news for Republican voters nonetheless;
WASHINGTON (AP) — Presidential candidate Donald Trump ruled out the prospect of a third-party White House bid Thursday and vowed to support the Republican Party's nominee — whoever it may be.The billionaire businessman announced his decision in a raucous news conference at Trump Tower, the gold-hued skyscraper in midtown Manhattan where he launched his surging and front-running campaign for president."I have signed the pledge," Trump said, adding that he intends to win the nomination himself and face whoever the Democrats nominate."So, I will be totally pledging my allegiance to the Republican Party and the conservative principles for which it stands, and we will go out and we will fight hard and we will win," he said.
It's been pointed out ad naseum on CNN that the pledge is non-binding. But there's a moral implication that will be a sticking point for many Trump voters should he go back on his word.