“Mormon” was the top one-word description given of Mitt Romney in a Washington Post-Pew Research Center poll released Tuesday. At that evening’s GOP debate, CNN’s Anderson Cooper asked candidates whether they agree with Robert Jeffress, an evangelical preacher who – after endorsing Texas Gov. Rick Perry at the Values Voter Summit – claimed Mormonism is a “cult.” No candidate took the bait and none have attacked Romney publicly over his faith (so far), but the recurrence of his faith as an issue raises some key questions.

What do Republicans (and Americans overall) actually think about Mormonism? Will Romney’s Mormon faith hurt him in the race for the Republican nomination?

The vast majority of Republicans and GOP-leaning independents tell pollsters it wouldn’t matter in their vote if a candidate was Mormon, a number that rose after Romney entered the race for the 2008 nomination. Three quarters said it wouldn’t matter in a June Post-ABC poll, similar to an Associated Press/GfK and CNN polls released this week. But one in five Republicans say it’s a negative factor in their choice, and research from the 2008 campaign shows that when Romney’s Mormon faith is brought to the front of voters’ minds, it has a clear negative impact.

Mormons unknown and different

Mormons make up about 2 percent of U.S. adults, and the rest of the public possesses only a passing familiarity with the religion. Only 11 percent of the public claimed to know “a great deal” about Mormonism in a 2007 Pew Research Center survey, while an additional 38 percent professed “some” knowledge. Perhaps as a result, over six in 10 said Mormonism is “very different” from their religion; that is almost as many as said Islam is very different.

More than a third of Republicans and GOP-leaning independents said Mormonism is not a Christian religion in the Pew survey. And while only 14 percent of Republicans who believe Mormonism is a Christian religion say they are “less likely” to support a Mormon, that jumps to 40 percent of those who say the religion does not match up to Christianity. For the record, both Romney and Mormons see themselves as Christians.

The criticism that Mormons are not Christians appears to have legs as an attack on Romney, according to John C. Green, a political science professor at the University of Akron. In a survey experiment, Green and his colleagues gave some voters a short biographical description of Romney, while others read his biography along with the fact that he was a local leader in the Mormon Church. They found that voters who read about his involvement in the Mormon Church said they were less likely to vote for him than those who hadn’t read that information. This effect was largest among those who said that Mormons are not Christians.

Issue was “activated” in 2008, but not yet in 2012

Less than a month before the 2008 Iowa Caucuses, Republican candidate Mike Huckabee – a former Baptist pastor – notoriously pondered whether Mormons “believe that Jesus and the devil are brothers.” Although he pleaded ignorance about Mormonism when pressed about his views, Huckabee’s campaign manager told the New York Times that the Huckabee “talked about the issue wherever he goes.”

Romney may have paid a price for such attacks at the polls. More than a third of Republican caucus-goers said it mattered a “great deal” that a candidate shared their religious beliefs according to entrance polls; 56 percent of these voters supported Huckabee while 11 percent backed Romney. Romney won almost 40 percent of the vote among those who said religion didn’t matter much.

White evangelical Protestants – a core Republican group that accounted for a majority of voters in the 2008 Iowa caucus and South Carolina primary – are somewhat more likely to see a candidate’s Mormon faith as a negative, and his support is lower among this group. In the latest Post-ABC poll, Romney’s earns 30 percent support among non-evangelical Republicans compared with 17 percent among white evangelicals. Despite the difference, white evangelicals make up almost a quarter of Romney supporters in polls since July, indicating that while some evangelicals may be hesitant to support a Mormon, plenty are willing to line up behind him. In hypothetical matchups against Obama, 74 percent of white evangelicals support Romney, almost identical to 75 percent who say they’ll vote for Perry.

Playing down controversies over Mormonism may work in Romney’s favor, and this year he is aided by a Republican field that seems reluctant to bring up the religion issue on the campaign trail. Green notes that “If these views were to be activated, it could pose a problem for Romney in the early primaries where there is a highly politicized evangelical community.”

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