WASHINGTON – Here we go again: More than three years after President Barack Obama took office, a survey suggests a majority of Republican voters in two deep South states still think Obama is a Muslim.

The Public Policy Polling survey asked likely Republican voters in Mississippi and Alabama, “Do you think Barack Obama is a Christian or a Muslim, or are you not sure?”

In Mississippi, 52 percent said they thought he was a Muslim. Those numbers were slightly lower in Alabama, where 45 percent thought the president was a Muslim. Released Monday, the survey polled 656 Republicans in Mississippi and 600 in Alabama who plan to vote in primaries in those states Tuesday.

Only 12 percent of Mississippi GOP primary voters and 14 percent of Alabama voters said they think Obama is a Christian.

Either voters in the deep South are unaware of Obama’s professions of faith, or they don’t believe him. In either case, in this presidential campaign, it appears voters care about the candidates’ personal religious views. But should it matter?

“I think that it’s very natural for a candidate to want to share their experience as a person of faith, if they are,” said Amy Sullivan, a former senior editor at Time magazine who covered religion and politics. “And it’s natural for voters to wonder.”

A person’s religious faith is a matter of great importance for many Americans, including those who run for president. Melissa Rogers, the director of the Wake Forest University Divinity School’s Center for Religion and Public Affairs, said faith and politics will inevitably mix.

“For some candidates, their religious affiliation, and upbringing and convictions really help shape who they are and what they believe in terms of their positions on policy issues,” said Rogers, who is also a non-resident fellow at the Brookings Institution. “In that case, it’s fine for a candidate to talk about that, just as they would talk about other aspects of their personal life and story.”

Faith is a major part of former Sen. Rick Santorum’s narrative; his Catholic religion guides his views on certain social issues, such as gay marriage and abortion rights. (He is against both.) He won the evangelical vote in three Super Tuesday states: Ohio, Oklahoma and Tennessee, but lost the Catholic vote in every state where data were available with the sole exception of Tennessee, according to the Pew Forum on Religion and Public Life. Santorum currently runs second in delegates to Gov. Mitt Romney in the race for the GOP nomination.

“People who are running for president have every right to say that they have a religiously informed conscience: ‘My religion guides me. It doesn’t dictate to me, but it guides my thinking, and I’m going to make plain where I think it should have some relevance,’” said Bill Donohue, the president of the Catholic League, a conservative-leaning Catholic rights organization. “And the voter can say, ‘Well I agree with that,’ or ‘I think that’s gone too far.’”

Romney tends to shy away from talking about how his Mormon faith shapes his political perspectives. He doesn’t highlight it in campaign speeches, and hasn’t made it a major issue on the trail.

Yet Romney’s “otherness” may deter evangelical voters. He’s received less support from that group in the primaries, and the evangelical vote eluded him in all but two Super Tuesday states, according to Pew data.

Mark Silk, a professor of religion in public life at Trinity College in Connecticut, said it isn’t fair to judge that as a response to Romney’s Mormonism – it’s partially based on his policy views.

“The significant religious voting blocks in the Republican primary (are) white evangelical Protestants,” Silk said. “They have been a crucial part of the Republican base, and they have not been happy with Mormons and with moderates. Mitt Romney sort of qualifies as both.”

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Although a candidate’s religious views are important to many in the GOP base, Republican National Committee spokesman Ryan Mahoney said they are only a piece of the puzzle.

“Religion can play into a larger perception that voters have of a candidate,” Mahoney said. “But they’re looking at a whole package, and they’re looking at four Republican nominees that have some better ideas for fixing our economy than Obama does, and that’ll play more of a role than religion will in the general.”

The main issues in this election are jobs, gas prices and the overall state of the economy, Mahoney said. At the polls, Republicans will consider these concerns more than a candidate’s religious views. Though 227,000 jobs were added in February, unemployment remained stuck at 8.3 percent, and gas prices rose to a national average of $3.80 on March 13.

Despite economic woes and rising prices at the pump, voters do care that a candidate is a good person. And some use religion to determine that.

“In my perfect world, it would be no different than a candidate sharing whether they were a Mets or Yankees fan,” Amy Sullivan said. “It tells you something about them. But it has become a proxy for learning about a candidate’s character and morality, and it is an incredibly inaccurate proxy.”

It’s especially hard to evaluate a candidate’s religious character if you don’t know what that religion actually is. Though Obama is a professed Christian, that hasn’t stopped high-profile people from questioning his faith.

“When Christians raise doubts about what the leader’s religious identity is, it inevitably turns faith into a political weapon,” Rogers said. “And that’s an abuse of faith.”