Transcript for Donald Trump Takes Aim at Hillary Clinton; Clinton Goes After Trump

Now to the race for the white house and Donald Trump in a showdown with Hillary Clinton and republican house speaker Paul Ryan who has yet to endorse the presumptive nominee. Tom llamas is at trump headquarters right here in new York. Good morning, Tom. Reporter: Amy, good morning to you. Trump said he was blindsided by Ryan's lack of commitment and over the weekend unleashing on the Clintons. Hillary Clinton's husband abused women more than any man that we know of in the history of politics, right? Reporter: Donald Trump showing nothing is off-limits in his road to the white house. The presumptive republican nominee spotlighting the Clintons' darkest days, trying to tie Hillary Clinton to her husband's air L affair with Monica lewinsky. She was a total enabler and they're going after me with women, give me a break, folks. Reporter: Trump making it clear that president bill Clinton is fair game even though trump's opinion on Clinton's sex scandals has evolved. Here's a guy, he was impeached because he lied. He lied. Do you remember the fabulous I did not have sex with that woman and then a couple of months later, I'm guilty. Reporter: But back in 2008, trump had a much different take. I mean, look at the trouble bill Clinton got into with something that was totally unimportant and they tried to impeach him which was nonsense. Reporter: The billionaire also saying this about women in America. All of the men were Petry field to speak to women anymore. Reporter: This as trump is also fighting some of the most powerful people in his own party. House speaker Paul Ryan announcing last week he's not ready to endorse Donald Trump. I'm just not ready to do that at this point. I'm not there right now. Reporter: Donald Trump firing back, suggesting to George he may not commit to supporting Ryan as the chair of the upcoming gop convention in Cleveland. Can Paul Ryan chair the convention if he doesn't endorse you? You're going to have to ask him. I have had so much support. Reporter: Insisting he can win with a fractured republican party. I think I'm going to go out and I'm going to get millions of people from the democrats. Reporter: And Sarah Palin not happy about speaker Ryan's lack of support. She's now vowing to take Ryan down in his next election. Because she's a huge trump supporter. George. Okay, Tom, thanks very much. Let's move on to Hillary Clinton, she's still in a race with Bernie sanders but taking on Donald Trump. ABC's Cecilia Vega with the latest. Reporter: Hillary Clinton and Donald Trump aren't even officially in a one-on-one yet but you wouldn't know that by the attacks that are flying and now Clinton is hoping that a trump candidacy might scare off some in the republican party and send them her way. Reporter: Donald Trump may have a nickname for Hillary Clinton. Crooked Hillary. Crooked Hillary. Reporter: But this morning, she has a new one for him, too. And they're presumptive nominee, otherwise called their presump does nominee. Reporter: Trying to brush off trump's one-liner as well as her lingering e-mail scandal. Huma abedin recently questioned by the FBI. I'm more ready to talk to anybody any time. Reporter: Clinton still locked in a primary fight with Bernie sanders. But she's laser focused on the general election. And not just winning over democrats Clinton is now trying to woo republicans, too. I'm asking people to come join this campaign and I have had a lot of outreach from republicans in the last days who say that they are interested in talking about that. Reporter: But her continued struggle to seem more likable ripe for snl parody. The first Barbie commander in chief. Reporter: First commercial about president Barbie, the doll that no one wants to play with it. I just don't like her she's too stiff. So much on snl this season. Now, Bernie sanders is still promising to stay in this race until the end. He's offered a new hint that he might be open to talks with Clinton about the vice president talk. Still several primaries to go. Let's talk to Matt dowd about all of this. Let's begin with Donald Trump and the split within the republican party. He surprised me when he said bringing the party together may not matter that much. Does the party have to be together? Does it have to be unified? I'm very different than everybody else. I don't think so. His point is, he can bring in a lot of democrats and independents, is he right? He's right about one thing -- he's very different than anyone who's run before. He needs to have 100% of the republican voters. If the split starts to emerging among republican voters it's hugely problematic for him. Back in 2012 Romney got more than 90% of the republican voters and still lost. Meanwhile, looking at the general election and this feud with Hillary Clinton over -- he believes that bringing up bill Clinton's troubles back in the 1990s is an effective counter to the woman's card. This is an issue that many republicans have been wanting to litigate in the past 20 years. He's basically saying Hillary Clinton who claims to speak on behalf women's voters is problematic in this area. I think is going to be back and forth. I think it's going to generate some sport for Donald Trump among the base of this. I don't think it's going to have any effect on the independent voters.

This transcript has been automatically generated and may not be 100% accurate.