Senate Leader Mitch McConnell and GOP primary challenger Matt Bevin. CQ Roll Call/Getty Images

The Tea Party candidate challenging Senate Minority Leader Mitch McConnell to a primary challenge insisted today that he does not support cockfighting despite being caught on an undercover video addressing a rally that was supporting the legalization of the bird fights.

Bevin insisted today that he had been invited to the rally to discuss his candidacy, saying people were "gathered to address various states' rights issues."

He apologized that his attendance may have "created concern on the party of many Kentucky voters."

"I am not and have never been, a supporter of cockfighting or any other forms of animal cruelty," Bevin said. "I am, however, a strong supporter of states' rights. Regardless of any personal views on this issue, animal rights are not an enumerated power granted to the federal government under the Constitution. Such decisions should be left to each state to decide.

I made the decision to speak at the gathering in Corbin because I support our 10th Amendment rights, not because I support or condone every topic discussed at the event."

Bevin, who is seeking to wrest Kentucky's Republican Senate nomination from McConnell, and his campaign have said repeatedly they thought it was a state's rights rally he attended in Corbin, but in the undercover video from WAVE 3 News, it's clear what the event is about with signs supporting the legalizing of cockfighting. Bevin even speaks right after a cockfighting activist who explained clearly why they were: "For the sole purpose of legalizing gamecock fighting at the state level."

The video emerged less than a month before the May 20 primary vote.

In recent weeks, Bevin insisted it was a rally for states' rights, not cock fighting. He told WHAS TV, "So, people at the first rally were there to discuss state's rights, everything from probably cockfighting, I don't know because I was gone, to helmet laws to growing of hemp etc." And he told the Courier-Journal, "It was a states' rights rally." In an interview with the News Journal, Bevin said he did not realize the event had anything to do with cockfighting.

But in the WAVE 3 News video of the rally, Gamefowl Defense Director Dave Devereaux asks Bevin: "Will you vote to support the effort to legalize gamecock fighting in the state of Kentucky?"

"I support the people of Kentucky exercising their right, because it is our right to decide what it is that we want to do, and not the federal government's," Bevin replied. "Criminalizing behavior, if it's part of the heritage of this state, is in my opinion a bad idea. A bad idea. I will not support it."

In a later interview with the reporter, Bevin says he wasn't "paying attention" to the speakers and when asked if he stands behind his support for cockfighting, Bevin says, "What I stand behind is people's ability to examine their First Amendment rights to speak about whatever they want to speak about."

Despite saying today he is against animal cruelty, earlier this month on WHAS radio Bevin again defended cockfighting, as well as dog fighting, by citing its historical roots in the state and in the nation's founding.

"You look at cockfighting and dog fighting as well, this isn't something new. It wasn't invented in Kentucky for example," Bevin said. "I mean the founding fathers were all, many of them, very actively involved in this and always have been. These things are part of a tradition and a heritage that go back for hundreds of years and were very integral early on in this country."

McConnell's team put out a scathing statement saying,"Matt Bevin's cockfighting episode will go down in history as one of the most disqualifying moments in Kentucky political history."

"Twenty years from now, we will all remember the time when the East Coast con-man thought so little of Kentuckians that he pathologically lied to us about absolutely everything until an undercover camera caught him red-handed at a cockfighting rally," McConnell press secretary Allison Moore said.

The campaign has already put out a radio ad this week using comedian Stephen Colbert making fun of Bevin over the cockfighting rally with the narrator saying, "Matt Bevin keeps making national headlines…but not in a good way," before mentioning some other low points in Bevin's campaign.

"Matt Bevin-a comedy of errors. But don't let the joke be on you," the narrator says.

Polls show Bevin lagging behind McConnell ahead of the May 20 primary, but the ad shows they are still taking Bevin's campaign seriously. Whoever wins the primary will take on Democratic candidate Kentucky Secretary of State Alison Lundergan Grimes.