Susan Walsh, File, Associated Press
FILE - In this July 20, 2012 file photo, President Barack Obama speaks in Ft. Myers, Fla. Most of America doesn't relate to Mitt Romney's religion but that may not matter in his race against President Barack Obama. Those are the findings of a new Pew Research Center poll a month before Romney will officially become the first Mormon presidential nominee of the two major political parties

A new survey confirms most Americans want a president who is religious. But the same survey shows more than a third of them don't know the faith of the sitting president or his Republican challenger.

Some 31 percent of voters surveyed by the Pew Research Center said they didn't know the religion of President Barack Obama, while 17 percent said he is Muslim. Slightly less than half (49 percent) correctly identified him as a Christian, but that is down from 55 percent back in late 2008.

Despite all the press about whether Mitt Romney's faith will help or hurt his GOP candidacy, just 60 percent of those surveyed knew he was a Mormon.

The myth that Obama is a Muslim persists and has apparently gained steam since he took office. In October 2008, 12 percent of voters Pew surveyed said the Democratic candidate was Muslim, and that group has grown to 17 percent today.

The numbers show the perception is largely partisan as 30 percent of Republicans identify the president as Muslim, up 14 percent from 2008. That news prompted a piece by Stephen Prothero, a Boston University religion scholar and author, posted on CNN, where he vented:

"There is something deeply troubling about the state of religion and politics in America today. And among those troubles is the cynical manipulation of religion for political gain — the use of God as a pawn in our political projects."

And those who practice Islam have similar feelings.

The AFP report on the Pew survey said that Muslim-American community leaders expressed concern that the lingering inability to recognize Obama's true faith showed a disturbing undercurrent in American politics, indicating a possible rise of Islamophobic discourse.

"For 17 percent of people to believe Obama is a Muslim shows there's a lot of fear-mongering and politicking in America," said Haris Tarin from the Muslim Public Affairs Council.

But Tarin also told the AFP that he opposes Obama's efforts to "constantly go out of his way to say he's a Christian."

Obama's Kenyan father was born a Muslim, his middle name is Hussein and he spent years in Muslim-majority Indonesia as a child, the AFP reported.

Joel Belz, founder of the evangelical bi-weekly World magazine, said that while he doesn't believe Obama is Muslim, many of those who do genuinely question the president's faith because "he equivocates on so many issues"

"His willingness to be on every side of even important issues leaves some thoughtful people to say, 'I'm not sure he's leveled with us on what his faith commitments are,'" he said.

David Weigel of Slate listed several issues that may have fueled theorizing about Obama's faith, but Weigel comes to a different conclusion.

"There's no follow-up, but you can count off the things that conservative Republicans haven't liked about Obama. The Cairo speech. 'Apologizing for America.' Wanting to close Gitmo. Afghanistan timetable. Siding with rebels in the 'Arab Spring,' and watching the Muslim Brotherhood take the lead from the rebels in classic Bolshevik/Menshevik tradition. Then, most recently, you've got theories about the Muslim Brotherhood infiltrating the government. The people who don't like Obama start with policy, then make assumptions about religion."

Prothero doesn't blame the disinformation about Obama's faith entirely on what he sees as politically motivated manipulators. He also says an electorate that is largely ignorant about religion must also take responsibility to become better informed.

"I have no problem with voters who care about the religious faith of their presidential candidates. But if religion is so darn important to our public life, can't we at least make a modest effort to learn something about it?" he asked.

"If so, let's start with these two indisputable facts: Mitt Romney is a Mormon. And Barack Obama is not a Muslim."