Conservative Sen. Lindsey Graham has made it clear he's extremely concerned about the threat of Islamic terrorism, but he isn't willing to outlaw a whole religion over it.

When a voter in Iowa suggested barring Islam in the U.S. in response to ISIS, Graham quickly shut him down, the Des Moines Register reports.

"You know what, I'm not your candidate," Graham said, cutting him off. "I don't want you to vote for me. I couldn't disagree with you more."

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As he's said before, Graham told his audience Sioux City on Thursday night that he would deal with ISIS by increasing the United States' military presence in Iraq. Explaining his terse response to the voter's suggestion to outlaw Islam, Graham told people, "I'm not trying to please him."

"I'm not putting up with that," he said. "He's got a right to say whatever he wants to say, but I have an obligation to the Republican Party, to the people of Iowa and the country as a whole to be firm on this. I'm not buying into that construct. That's not the America that I want to lead."

Graham demonstrated a few times in Iowa his willingness to speak candidly. In an interview from Iowa with the Huffington Post, the longtime senator teared up talking about his friendship with Vice President Joe Biden.

"If you can't admire Joe Biden as a person, then probably you've got a problem," he said, calling the vice president "the nicest man I think I've ever met in politics."

Graham has a long way to go if he wants to gain traction in Iowa, one of the first states to nominate presidential candidates for the Republican and Democratic parties. A recent Quinnipiac poll of likely Iowa GOP caucus goers showed Graham was registering at just 1 percent support.