Despite his promise to avoid attacking his opponents during the Republican presidential primaries, former House Speaker Newt Gingrich said on Thursday that Texas Rep. Ron Paul’s popularity comes from “people who want to legalize drugs.”

Gingrich then went on to criticize Paul’s foreign policy views as naïve.

“[Paul] is a guy who basically says, if the United States were only nice, it wouldn’t have had 9/11,” Gingrich said during a radio interview, according to National Journal. “He doesn’t want to blame the bad guys. … He dismisses the danger of an Iranian nuclear weapon and seems to be indifferent to the idea that Israel could be wiped out.

“And as I said, I think the key to his volunteer base is people who want to legalize drugs.”

While just a week ago Gingrich was widely seen as the favorite to win Jan. 3 Iowa Caucus, a recent Iowa University poll showed Paul now leading the former speaker of the House in the Hawkeye State. Gingrich has also been the target of round-the-clock attack ads in the state funded by Paul, Texas Gov. Rick Perry and political groups backing former Massachusetts Gov. Mitt Romney.

Gingrich has been critical of his opponents’ ads and on Wednesday, challenged Romney to a one-on-one debate.

“I’m happy taking the heat, why doesn’t he join me in the kitchen?” Gingrich told Fox News.

For his part, Romney says he has no control over the super PACs backing his candidacy and attacking Gingrich in Iowa. Gingrich dismisses that claim, and says Romney could stop the ads if he wanted to.

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