Transcript for Joe Biden Bows Out of Presidential Run
from vice president Joe Biden. Reaction coming in after he announced he will not be running for president and ABC's David Wright is here with more on that. Good morning, David. Good morning, Amy. Among the 2016 candidates today respect for the vice president and relief that the field of candidates is finally set. The republicans now focused exclusively on Hillary Clinton. After flirting with the idea for months -- Mr. President, thank you for lending me the rose garden for a minute. Reporter: But Joe Biden called it quits just a few steps from the oval office. Unfortunately, I believe we're out of time. The time necessary to mount a winning campaign for the nomination. Reporter: Clearly, Biden wanted to run. But he said his grief over the death of his son beau had its own timetable. Sooner rather than later when you think of your loved one it brings mile to your lips before it brings a tear to your eyes, well, that's where the Bidens are today. Thank god. I think he did the smart thing because, frankly, I don't know that he would have won. Reporter: Campaigning in Iowa Donald Trump didn't sound too disappointed. Frankly, I really want to run against Hillary. I really do. Reporter: On Twitter adding sharply I'd rather run against Hillary because her record is so bad. Mike Huckabee tweeted I'm the only gop candidate who defeated the Clinton machine. Only bobby jindal barely at 1% in the polls himself even bothered to acknowledge there was anyone else. Democrats are now left with a socialist or a candidate under FBI investigation. He tweeted. It pretty much guarantees Hillary will be the person that we're running against. Reporter: The RNC released a new video suggesting that is how they see it too. And whatever else may be on the agenda for them today you can bet all of the republican candidates will drop whatever they're doing to watch the benghazi hearings hoping for something they can use. All right, David, thank you. No question about that. Let's talk more with Matt dowd. He joins us this morning of a new poll out from "The des Moines register." Hillary holding her lead above Bernie sanders, 48% to 41%. 80% favorability among democrats in that state. Is Ben Carson right when he says this combined with Biden getting out of the race guarantees her nomination pretty much? I don't think it guarantees it, George, but the one big hurdle was removed by the vice president taking himself out of the race but she still has a few hurdles left, one is the benghazi hearing today. She has to get through that reamably well but Bernie sanders is still there close behind. Bernie sanders has a path, it's a very limited path but he has to win Iowa which he's close in and win New Hampshire where he's tied or ahead in but the path for Bernie sanders got a lot smaller as of today. Let's talk about the republicans. We just heard from Ben Carson. There's a new poll out in Iowa from quinnipiac showing he pulled ahead of Donald Trump, 28% to 20%. A real milestone. Reporter: I think this is significant because for more than 100 days Donald Trump has led every national poll and every single state poll. This is the first to come out that shows somebody else with a significant lead. The owe part of the poll that should be troubling to Donald Trump is Marco Rubio has taken a big jump up in the poll and looks like he's becoming the alternative establishment candidate in this race. That's what I want to ask you about. He has polled well ahead of a couple of points there in Iowa of Jeb bush who is supposed to be coming in with all these advantages but continues to slip. He's continuing to slip but I think part is debate performances. Part of it is performances on the trail but part is people want somebody else in the republican party that doesn't have the bush name. Bush when you look at his favorabilities in Iowa especially in some of the early states is more negative than positive and so that's Jeb's problem. Marco looks like he's the establishment candidate on the rise. Okay, Matthew dowd, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.