Transcript for Bernie Sanders Vows to Stay in the Race Right Up to the Convention

Now, to the major developments on the democratic side tonight, as well. Hillary Clinton with a decisive win in Nevada, the south Carolina primary just five days away now. Celebrating on that stage with former president bill Clinton. And tonight here, you will hear a shift in her message, her tone. Meantime, Bernie sanders this evening, not backing down. He was asked directly today, does he still have a path to the nomination? And you will hear how he answers. Here's what he's up against. The latest poll in south Carolina showing Clinton with a nearly 30-point lead. ABC's Jonathan Karl on the campaign tonight. Reporter: A newly-energized Hillary Clinton is back on top, Thank you, Nevada! Thank you so much! Reporter: She's confident enough to make this extraordinary admission. I think there's an underlying question that maybe is really in the back of people's minds, and that is, you know, is she in it for us or is she in it for herself? Reporter: And now, a shift in tone. Clinton talking less about herself, less about "I" and more about "We." We hear you. We see you. We're incredibly grateful to you. Because we're in this together. We are all in this together. We all have to do our part. Reporter: Clinton won 76% of the african-american vote in Nevada, support she's counting on in South Carolina, where more than half of democratic voters are african-american. She's launched yet another new ad, featuring one of the most well-recognized voices in America -- actor Morgan Freeman. She says their names. Trayvon martin. Trayvon martin, shot to death. Dontre Hamilton. Unarmed. Andra Sandra bland. Sandra bland did nothing wrong. Reporter: And Bernie sanders is turning to another prominent african-american actor -- Danny glover. Today in Boston, he attacked Clinton as a political opportune is. And the people of the united States need to know the difference between hastily adopted campaign rhetoric, and the real record and the long-held ideas of the candidates. Reporter: When asked trektly if he still has a path to winning the democratic nomination, his answer was emphatic. The short three-letter answer is y-e-s. And Jon Karl with us live tonight, as well. After a near tie in Iowa, and a bruising loss in New Hampshire, what a shift, Jon. It's actually the Clinton team now pointing to the math tonight? Reporter: That's right. We look at delegates. They are virtually tied among the delegates won in those three states, but you add in the so-call superdelegates and Hillary Clinton has a big lead. A lead she expects to add to over this weekend in south Carolina. But David, I've got to say, they are not overly confident. They believe that Bernie sanders will do well on super Tuesday and is likely to win several states and more delegates. All right, the fight continues. Jon Karl tonight, thank you. We're going to turn next to

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