Sen. Lindsey Graham Lindsey Olin GrahamGraham: GOP will confirm Trump's Supreme Court nominee before the election Fox's Napolitano: Supreme Court confirmation hearings will be 'World War III of political battles' Grassley, Ernst pledge to 'evaluate' Trump's Supreme Court nominee MORE (R-S.C.) says he will trounce Donald Trump Donald John TrumpBubba Wallace to be driver of Michael Jordan, Denny Hamlin NASCAR team Graham: GOP will confirm Trump's Supreme Court nominee before the election Southwest Airlines, unions call for six-month extension of government aid MORE if the two presidential candidates face off in South Carolina's primary, calling the businessman a “complete idiot.”

“Come to South Carolina, and I’ll beat his brains out,” Graham — who barely registers on a litany of polls dominated by Trump — said in an interview on CNN Tuesday.

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Graham repeatedly characterized Trump supporters as a frustrated group that believes President Obama is a Muslim who was born in Kenya.

“There’s 30 percent of my primary electorate that believes that Obama’s a Muslim, that he’s born in Kenya, and that would deport everybody,” Graham said after being shown a poll of South Carolina voters, 30 percent of whom support Trump in the Republican presidential primary.

“So there’s a dark side of politics that Mr. Trump’s appealing to,” he added.

Graham also described the real estate tycoon's rhetoric on immigration as demagoguery.

“Demagoguing immigrants — he’s not the first guy to do this, and he won’t be the last, and there’s always a market for it, but it’s not sustainable,” Graham said.

The senior senator from South Carolina also said that Republicans will “get killed” in a general election if Trump is the presidential nominee.

“His approach to describing immigrants are hurting us with Hispanics,” Graham said. “The way he attacks women is going to a deathblow to the future of our party.”

Trump taunted Graham Tuesday morning on Twitter, pointing to his 26-point primary lead in the longtime senator's home state.

Graham has previously called Trump a “jackass” and a “political car wreck.”