*A startling increase in the number of Americans who believe, incorrectly, that President Barack Obama is a Muslim is spurring fresh debate about whether he needs to – or should – do more to convince the public of his Christian faith.

Two surveys released Thursday indicate that religious rumors that have dogged the first African American president since his 2008 presidential campaign are surprisingly widespread, and may have actually gained traction during his presidency. One of the polls, commissioned by Time magazine, contains a jaw-dropping finding: nearly half of Republicans-46 percent- believe Obama is a Muslim.

“We have had a war of attrition over Obama’s religious reputation since the campaign,” said John Avlon, author of “Wingnuts,” a book on the political fringe. “It all comes from the same place: this idea that he’s the other – alien.”

Doubts about his religious views were stoked, Avlon said, when Obama quit Trinity United Church of Christ – a prestigious African American congregation in Chicago – amid the controversy over Rev. Jeremiah Wright’s incendiary remarks about race, but didn’t immediately join another church. When he came to Washington as president, many expected Obama would select a new church or sample many different ones. But in more than 19 months he’s been in office, he has been seen heading to the golf course more than to church.

“When Rev. Wright blew up, and Obama left that church, his failure to find another congregation was seen as evidence that it was all a fraud to begin with – for some folks on the far right,” said Avlon, a former speechwriter to Rudy Giuliani, referring to the controversy over the African-American minister’s remarks about race. “The fact that [Obama] hasn’t found a new congregation that he attends on a regular basis is used to just underscore that.”

“There’s enough misinformation out there that it can cause confusion, and there aren’t photographs of him attending church every Sunday,” noted Lee Miringoff, director of the Marist Poll.