Texas Gov. Rick Perry, facing a conservative backlash over his labeling as heartless those who oppose his state law giving college tuition breaks to the children of illegal immigrants, said Wednesday that the tone of his remarks was “inappropriate.”

In an on-camera interview with Newsmax.com, a conservative media outlet, Perry said he had been “over-passionate” in his answer to a question about the law during last week’s GOP presidential candidates debate.

“I probably chose a poor word to explain that,” Perry said in the interview. “For people who don’t want their state to be giving tuition to illegal aliens, illegal immigrants in this country, that’s their call, and I respect that.”

Although he walked back his remarks, Perry stood by the legislation and noted that it passed in 2001 with the support of all but four legislators in Texas.

“I was probably a bit over-passionate by using that word. And it was inappropriate,” Perry said. “But here’s what I do believe: that it is a state’s sovereign right to decide that issue for themselves.”

In last Thursday’s debate in Orlando, Perry said, “If you say that we should not educate children who have come into our state for no other reason than they’ve been brought there by no fault of their own, I don’t think you have a heart,” Perry said. “We need to be educating these children, because they will become a drag on our society.”

The comment drew boos from thousands of Republican activists in the debate audience and reverberated across the GOP political landscape. Perry’s rivals have tried to use the issue as a wedge to drive between Perry and the party’s conservative base, which seeks tougher treatment of illegal immigrants.

Mitt Romney, Perry’s top rival for the nomination, is sharply criticizing Perry’s law on the stump, noting that as governor of Massachusetts he vetoed a similar law. During a town hall meeting Wednesday in Goffstown, N.H., Romney reportedly brought up the immigration bill and said he vetoed it because “I’d rather give [benefits] to you. I’d rather forgive your loans than give it to people who are here illegally.”

In an appearance Wednesday on MSNBC’s “Morning Joe,” Romney defended comments from Erick Erickson, the editor of a prominent tea party blog, Redstate.com, suggesting that Romney is not conservative enough by pointing to Perry’s more moderate immigration stances.

“I think if we were to ask, well, now, which is the more conservative position on immigration, Mitt Romney’s or Rick Perry’s, I think Eric would say, well, actually Mitt Romney’s is the more conservative position,” Romney said.

Romney hasn’t been alone in pummeling Perry. On Tuesday night, New Jersey Gov. Chris Christie — who is not a candidate — criticized Perry’s immigration stance during a high-profile appearance at the Ronald Reagan Presidential Library and Museum.

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