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MYRTLE BEACH, S.C. — Among conservatives, Donald Trump can typically do no wrong — until he attacks Ted Cruz.

On Saturday, Trump drew boos from a grassroots conservative crowd during remarks at the South Carolina Tea Party Coalition Convention for his attack on Cruz’s previously undisclosed loans.

"You give a campaign contribution to Ted Cruz, you get whatever the hell you want,” he said, before boos erupted from the crowd.

Trump went on as the boos grew louder: "Say whatever you want, it’s okay, he didn’t report his bank loans. He’s got bank loans from Goldman Sachs, he’s got bank loans from Citibank, folks, and then he acts like Robin Hood?"

Related: Trump Calls Cruz 'Hypocrite' on Loans

One man in the crowd, 71-year-old Air Force veteran Joe Bates, stood up and shouted angrily, wagging his finger at the candidate.

Trump continued: "You know, say whatever you want, but it doesn’t work that way."

It was a stark illustration of the political perils the two candidates face in attacking each other as they sprint toward the early primary contests. Each risks losing ground among conservatives that haven’t yet made up their minds between the two candidates, or inflaming their opponent’s base against them.

With that in mind, Cruz had, up until last week, carefully avoided taking on Trump directly.

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But with two weeks till the high-profile Iowa caucuses, and the two candidates just points apart in most polls of Republicans there, this week the gloves came off — culminating in a number of explosive exchanges between the two at Thursday’s debate over Cruz’s claim to U.S. citizenship and Trump’s “New York values.”

The feud boiled over to the weekend, with both Cruz and Trump trading jabs on the campaign trail — Cruz saying in upstate South Carolina that Trump had flip-flopped on key issues, and Trump previewing his Robin Hood line in New Hampshire.

Related: Ted Cruz Rips Donald Trump for 'Springing Out of Bed to Tweet'

But in front of a crowd of grassroots conservatives, many activists who had driven for hours to see one or the other, Trump went on the attack while Cruz left Trump out of his remarks just hours before.

It’s a risky bet for Trump, as even some conservatives have criticized Trump for his attacks on Cruz in recent days.

Influential conservative talk-radio host Mark Levin told Trump in a Facebook post to “either cut the crap — your accusations this morning that Cruz is Canadian, a criminal, owned by big banks, etc. — or you will lose lots and lots of conservatives.”

Some at Saturday’s event said Trump’s attacks on Cruz had turned them off from him.

Kathy Hughes, a 68-year-old retired teacher from Mount Pleasant, South Carolina, said she was “so excited” to see Trump until he trained his fire on Cruz, and now she’s sitting his speech out.

“He has degraded himself now to me,” she said.

Hughes said she felt like Trump had done away with his commitment to telling it like it is in part because he took Cruz’s attacks on New York personally.

“I was pleased that he has put issues forward that many of the candidates did not want to talk about and they’ve been forced to talk about. He has kicked political correctness to the curb — until Ted said something about New Yorkers — and then suddenly Mr. Trump became very sensitive,” she said.

Related: Did Cruz Miss With His 'New Yorke Values' Jab?

But even if some conservatives are fed up with the attacks, there was evidence at the convention that they work.

Joe Bates, the man that wagged his finger at Trump, declined to be interviewed but his wife, Annie, said that the both of them were sick of the attacks.

“You just state what you can do! Each person does something different. There’s no need knocking the other person,” she said.

They were also undecided. But while they were frustrated with the sparring, Annie Bates said they wouldn’t turn her off from one candidate or the other.

And she said she planned to go home and research what Trump had said about Cruz’s loans.

“It makes me look at what they’re saying about each other,” she said. “That’ll be a factor in what I decide.”