Transcript for Joe Biden Reflects on His Personal Decision Leading to the 2016 Presidential Race
Robin, you had a special guest in times square on politics. Vice president Joe Biden stopped by and his mission to fight cancer inspired by his beloved son and of course the conversation turned to politics. Very open discussing Donald Trump, Hillary Clinton and whether or not he himself should have run for president. You bring up the next president, we're all anxious to she -- Who she is. No, I'm just kidding, robin. I know. But there's a new poll out showing in three key battle states that Hillary Clinton and Donald Trump are neck and neck. Do you think that he's been underestimated? Oh, yeah, I think he has been underestimated from the beginning but I also think that it's really very, very early but I think what's going to happen here is that the constant attack coming from republican side, the sort of vitriol, I don't think it's going to wear well over the next several months. So I feel confident that Hillary will be the nominee and I feel confident she'll be the next president. No regrets? I know before you said you didn't run -- that you knew it was the right decision for your family. Look, I -- I planned on running. It's an awful thing to say. I think I would have been the best president but it was the right thing, not just for my family, for me. No one should ever seek the presidency unless they're able to devote their whole heart and soul and passion and to just do that and beau was my soul. I just wasn't ready to be able to do that. My one regret is my beau is not here. I don't have any other regrets. But this is in ray way carrying on -- It is. Your son. I remember talking with you that day in January right after the president had put you in control of mission control. Let's make America the country that cures cancer once and for all. What do you say, Joe? Let's make it happen. How's it been for you this year? Well, you know, it's kind of bittersweet but this is -- this allows me to pour all my energies into doing something that hopefully will five years from now if someone is diagnosed with what my beau was diagnosed with, they live. And there's so much promise out there. And there's so much more to the interview with vice president Biden in our next hour and he just really opens up about how his son inspires him in everything he does and Hess latest on his mission to help millions fight cancer. He's really seized by this mission. He truly is and we'll have that in our next hour.
This transcript has been automatically generated and may not be 100% accurate.