Transcript for Donald Trump and the New Truce With Republicans
We turn now to the race for 2016 this evening. Taking a brand new turn, Donald Trump and a bold new pledge. You'll remember that first debate 24 million watching and the question, raise your hand if you won't promise not to run as an independent. Raise your hand now if you won't make that pledge tonight. Donald Trump, the only one raising his hand then, to many boos in the crowd. Tonight trump signaling a new pledge, ruling out a third party run if he doesn't win the republican nomination. ABC's Tom llamas with trump and the sign he held up today. Reporter: Tonight, Donald Trump saying what so many republican leaders wanted to hear. I will be totally pledging my allegiance to the republican party and the conservative P principles for which it stands. Reporter: This afternoon, gop chairman reince priebus ducking into trump tower. No other candidate getting this type of personal attention. Rival Jeb bush mocking the whole affair tweeting out this photo, voted republican since 1972, and on the trail in New Hampshire today needling trump by speaking Spanish. So here I am. A candidate for president of the United States, believing we should campaign with our arms wide open. Reporter: Trump yesterday saying bush should set an example by speaking English. Can you clarify your comments, what you said about Jeb bush. Well, I think that when you get right down to it we're a nation that speaks English and I think while we're in this nation we should be speaking English. Reporter: David, Jeb bush says trump will tear the party apart, but tonight a new national poll shows trump stronger than ever with 30% of the vote. Ben Carson in second place and bush in third place with single digits. David?
This transcript has been automatically generated and may not be 100% accurate.