Transcript for Donald Trump: 'If I Don't Win, I Wasted My Time'
Reporter: When we made our next pick, we knew there would be controversy. After all, controversy sticks to this man like hair spray. But he is a fascinating person, and if you don't believe it, just ask him. Whether Donald Trump will become president or even his party's nominee is still in doubt. What isn't in doubt is that some of the things he has said over the past six months have framed this election so far and may ultimately decide it. Donald Trump talks a lot about winning. He is a winner. We will have so much winning if I get elected that you may get bored with winning. Reporter: And he wants America to be a winner. We need somebody that can take the brand of the united States and make it great again. Reporter: And this year, that message resonates. Did you just wake up one day and say, "I'd like to be president"? I look at what's happening with our country. I look at the stupidity of our leadership. I look at the decisions that are made that are so bad, and I just felt I had to do it. Reporter: There are up to 7 million Muslim Americans. Do you regret at all your proposed ban on muslims coming to America? Not at all. First of all, it's not a ban long-term. This country, our country, has to get its act together. One thing I have to say -- I have tremendous friendships in the Muslim community. Tremendous relationship. They're great people. But we have to get smart, and the people that I know in the Muslim community agree with me. Reporter: Are you a bigot? Not at all. Probably the least of anybody you've ever met. Reporter: There was a recent mass shooting in San Bernardino, it seems, with a link to Isis. You have said that guns should be carried to fight back against terrorism. Wouldn't that produce more violence? No, much less. Look. I'm a big believer in the second amendment. The bad guys will always have guns, Barbara. So Paris -- boom, boom, boom. If you look at California, nobody had guns except the bad guys. If you had three or four people like me -- I have the right to carry. I have a license to carry. If you had people like me in that room, and somebody started shooting, I guarantee you we're going down shooting. Reporter: You are carrying a gun now? No. Not now. Reporter: Ordinarily, do you carry a gun? A lot of the time. I have the right to carry. Reporter: You have said that Hillary Clinton does not have enough energy to be president, but you and she are about the same age. Right. Reporter: So? Well, I have a lot of energy. Look. She doesn't have the strength or the stamina. Reporter: Her people would argue as secretary of state, and even now, she travels all over the world, she speaks everywhere. Well, not really. Reporter: Is it because she's a woman? Is that what you're saying? If you look at Hillary, she'll do an event, and then she goes back home and she goes to sleep. I mean, you don't see her. Reporter: You don't know that. I think so, though. I think so. Reporter: Well. Are you sure that you can beat Hillary Clinton? I think I will beat Hillary very easily. She was a terrible secretary of state. The world blew up around her. I'm leading in the polls, and I think I'll beat her. Reporter: You have said that if you don't win the presidency, this is all a waste of time. Correct. If I don't win, I wasted my time. It's all about winning because I won't be able to put my ideas into play. Politicians -- I've dealt with them all my life. They don't have it. They will never be able to straighten out China. We're losing in terms of trade imbalance. $400 billion a year with China. They can't do anything about it. I know exactly how to solve the problem. Reporter: If you lose the republican nomination, are you a loser? In a certain way, yeah. Hate to say it. If I lost the nomination, yeah. I guess I'd call myself a loser. I've never said that about myself before. Look. I want to win. I want to make America great again. If I lose the nomination, not so good. Reporter: Let's say you become the president. When you leave office, in one word, what would you like your legacy to be? A victory.
This transcript has been automatically generated and may not be 100% accurate.