This is a rush transcript from "On the Record," April 12, 2016. This copy may not be in its final form and may be updated.
GRETA VAN SUSTEREN, FOX NEWS HOST: The Colorado delegate process is under a microscope. Donald Trump and his supporters are outraged. Senator Ted Cruz swept all 34 of Colorado's republican delegates.
And in response, Trump says the Colorado system is rigged. But at least one Colorado politician is defending the state's practice. Colorado Senator Cory Gardner goes "On the Record" from Capitol Hill. Good evening, sir.
CORY GARDNER, COLORADO SENATOR: Good evening.
VAN SUSTEREN: OK. So, Donald Trump says it's rigged. You say it's not rigged. So, what else do you say about this?
GARDNER: Well, look, this is a grassroots process. This has been in effect for about 100 years in Colorado. Donald Trump has known the rules since last August. He decided not to show up. Elections are won by those who show up and Ted Cruz showed up.
VAN SUSTEREN: So, why do you think there is so much, you know, so much heat on this? And you've got that tweet from someone who apparently at least reports to be part of the Colorado Republican Party about getting Trump?
GARDNER: Look, there is investigation into the tweet that went out after the nomination was secured by at least the number of delegates secured by Ted Cruz. But the bottom line is this. Donald Trump goes in to meltdown when he doesn't get his way.
In this case, he lost 34 delegates that he could have won had he participated in the process. Had he had an organization. Look, Colorado is not taken by celebrity or flesh. It's taken by work horses and Ted Cruz proved to be the work horse that won these delegates, 34 of them.
I was on the floor of the convention the entire day. I talked to hundreds of supporters, delegates, talked to dozen of Trump supporters. Dozens of Kasich and Cruz supporters. Not one of them complained about the process to me.
In fact, Donald Trump's own surrogate didn't complain about the process until they lost all 34 because they didn't do the work.
VAN SUSTEREN: Did it make a difference that -- correct me if I'm wrong, but I think Senator Ted Cruz actually went out and spoke to the group and I don't think that Senator -- I mean, I don't think Donald Trump or Governor Kasich did. Am I right on that? And if so, am I right did that have made a difference.
GARDNER: You're correct. It made a huge difference. I think if you look at Stephen Miller, he was the surrogate for Donald Trump who spoke before the entire convention, Senator John Sununu who spoke before the entire convention.
Look, they both addressed the convention and the delegates twice during the two days of the process. But Ted Cruz is the only one who showed up in person. And there are multiple videos that you can find on YouTube about the Colorado convention and you can see the energy and the enthusiasm for Ted Cruz throughout the thousands of people.
But for Donald Trump to be smirch the reputations of thousands and thousands of Colorado republicans who took time away from work, who took time away from family to be a volunteer delegate to this process and then to say that they're corrupt, it's simply unacceptable.
VAN SUSTEREN: I have to say, what happened last August to the straw poll?
GARDNER: It was a decision by the state party not to do a straw poll. In fact, the straw poll was done in 2012. It wasn't binding. They decided not to do a straw poll back in August.
Look, I'm not defending this process. What I'm defending is the fact that the Colorado republicans followed the process that's been in place since President Taft.
VAN SUSTEREN: And I guess that the problem is that when you get this tweet we did it, never Trump. And as a Colorado GOP, it's a, you know, that is sort of a show stopper in terms of whether or not it looks like the Republican Party was, you know, trying to be unfair to Donald Trump.
GARDNER: Well, look, they ought to find out how that happened. They have to find out who did it, and they have to fire whoever it was, absolutely. But I don't think that means that you turn around and you issue death threats to the chairman of the Colorado Republican Party. I don't think it turns around and you call the 65,000 people.
VAN SUSTEREN: Were there death threats?
GARDNER: Absolutely there have been death threats.
VAN SUSTEREN: Who does -- well, I guess all I can say we are sure are wound up this election season. Anyway, thank you, senator.
GARDNER: Thank you. Thank you.