"What's happening in the Republican Party is pretty historic. When you look at voter registration against the Democrats, it's never been better than in 25 years. Our fund-raising in the first quarter at the RNC was an all-time record," Priebus told CBS News in an interview.
"We've raised more money than we did in 2012. What I'm telling you is that the fundamentals are actually the opposite of the narrative. Now, clearly, when you have a race where you've got 17 candidates, and as of late, two very serious candidates with serious campaigns, it's not easy. It's hard," he said.
Priebus said it is time to unite the party. "It's time to come together."
He said Donald Trump is ready to roll up his sleeves and get to work and lashed out at Democratic presidential frontrunner Hillary Clinton.
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"I think Hillary Clinton still has a lot of work just to win her nomination now. Obviously she's in the driver's seat. But yet you do have to win at some point if you want to be the nominee and she needs to figure out how to win," he said.
After the win in Indiana, he said it is obvious that Trump would get the 1,237 delegates, necessary to be the party's presidential nominee.
"We have to have a nominee at 1,237, and the delegates on the floor have to vote. But I think the momentum is there. We've got a candidate that is winning in every single state. I mean, a week earlier, I don't think he had lost a county in six states," he told CNN in another interview.