Rand Paul says he's going to spend "every waking hour" trying to stop Donald Trump from getting the Republican nomination, saying Trump as the nominee would guarantee a Republican loss in the general election.

"Think if we, the Republican Party, becomes the party of angry people, that insinuate that most immigrants are drug dealers or rapists, that's a terrible direction for our party," the Kentucky senator and presidential candidate told the Alan Colmes Show on Thursday. "We are never going to grow as a party, we are never going to increase our vote among the Hispanic population, the black population, among women, all of those things we need to expand our party, Donald Trump takes us in the wrong direction.

"He would be a disaster," he added. "We'll be, we'll be slaughtered, in a landslide. That's why my every waking hour is to try to stop Donald Trump from being our nominee."

Still, Paul said he would support Trump should he win the nomination.

"I'm a Republican, and I think if you don't support the nominee, it harms even those like myself, because for example, I was not the establishment pick when I ran for the U.S. Senate, but I agreed that I would support them if they won," he said. "But they also agreed to support me. So it works both ways. It sounds terrible, 'who are you going to support? Donald Trump.' But I expect Donald Trump to support me as well, if I win."

Asked if he has more in common with Libertarian candidate Gary Johnson than Donald Trump, the Kentucky senator said yes and no.

"In some ways yes and in some ways no," he said. "I don't really know his platform, but I do know that the Republican Party has allowed a libertarian-leaning person like myself to actually become a U.S. Senator, and that I've worked very hard to make the party more libertarian and more constitutionally conservative. And I think it's been for a good thing."

Paul said the pundits who question if he is "libertarian enough" are speaking nonsense.

"You know, I think I always just tried to be who I am," said Paul. "Everybody, every pundit out there tries to say 'oh you're not libertarian enough," but if the problem were if I'm not libertarian enough, and that's why the poll numbers are not higher, that would be an argument that oh, 'libertarians are voting for Donald Trump,' so it doesn't really make any sense. But I have to be who I am. I'm a limited government constitutional conservative. I have some libertarian feelings ,and it's harder if there's a purity test for everything to determine what is purely right or wrong."