The stubborn misperception among a wide swath of the population that President Obama is not a Christian has laid bare a host of difficult realities in the United States; from the notion that being a Muslim would hurt him with voters to whether the perception is fueled by his race.
On top of the ongoing fracas over an Islamic center planned near Ground Zero, it also exposes a religious barrier in U.S. politics that could prove more persistent than gender or race.
A president's faith matters to many Americans. It was seen as a milestone when John F. Kennedy, a Catholic, was elected president after he went to great lengths during the campaign to insist that his religion would not affect his policies.
The Constitution enshrines clearly that religion should not matter.
"... no religious test shall ever be required as a qualification to any office or public trust under the United States," according to Article Six.
But Kennedy remains the only Catholic to attain the post.
And a 2007 Pew survey found that 45 percent of Americans said they would be less likely to vote for a Muslim. 61 percent said they would be less likely to vote for an atheist. Only 25 percent said they would be less likely to vote for a Mormon candidate. Sixteen percent said they would be less likely to vote for an Evangelical and 11 percent would be less likely to vote for a Jewish candidate. Far fewer, six percent, said they would be less likely to vote for someone who is black.
Bobby Jindal is of South Asian descent and is the Republican governor of Louisiana. But he is also Catholic, a much more prevalent religion in Louisiana than the Hinduism of Jindal's parents.
Nikki Haley, a Republican, stands a good chance of being elected as the first female governor of South Carolina. She too is a convert to Christianity, a fact the former Sikh makes clear on her website.
"'The pigment of Obama's, Jindal's or Haley's skin does not seem to matter,' goes the popular narrative, but Christian faith is a foregone criterion for electability," Aseem Shukla, co-founder of the American Hindu Society, wrote in Newsweek. "A religious litmus test is clearly in play."
For many Americans, however, a candidate's faith is extremely important because it can give a hint to his or her beliefs, said Tom Minnery, senior vice president for Focus on the Family, an evangelical organization that promotes its causes in politics.
Not All Founding Fathers Believed
"It is Important for candidates to have a biblical world view," Minnery said. "A view that says there is right and wrong and good and evil and the rights come from a creator. And that is God, not government. Those are key beliefs."
Some founding fathers, such as Thomas Jefferson, had complicated relationships with religion that would be more difficult for voters to stomach today.
"Question with boldness even the existence of God; because if there be one, he must more approve the homage of reason, than that of blindfolded fear," Jefferson wrote to his nephew.
"Think if this guy ran for president today and someone googled him," said Sean Faircloth, executive director of the Secular Coalition of America, which advocates for a strict separation of church and state and encourages acceptance of nontheists.
Three Presidents, Jefferson, Abraham Lincoln and Andrew Johnson, were not affiliated with a sect of Christianity. But Lincoln often quoted the Bible and referred to God.
There have been some notable runs for the presidency by non-Christians: Connecticut Sen. Joe Lieberman, who is devoutly Jewish, was 537 votes in Florida in 2000 from being the first non-Christian vice president. But he failed miserably when he ran for president himself.
Mormon Mitt Romney, the Republican former Governor of Massachusetts, who failed to get the Republican nomination in 2008, will test the Protestant lock on the presidency if he runs again for president in 2012.
There is growing religious diversity in Congress, where the 2006 election saw the first-ever elections of both a Muslim, Rep. Keith Ellison of Minnesota, and two Buddhists in Reps. Hank Johnson, D-Ga., and Mazie Hirono, D-Hawaii.
Divorce Between Religion, Politics Unlikely
In 2008, a second Muslim, Andre Carson, D-Ind., was also elected.
The proportion of Muslims in Congress -- 0.4 percent -- roughly mirrors their imprint on the larger population, 0.6 percent, according to a Pew study of faith in Congress.
Ellison caused a stir in 2007 when he was sworn into office on a Quran instead of a Bible.
The Pew study shows a similar correlation among Protestants, broadly, who make up about 51 percent of the population and 54 percent of Congress. Catholics are better represented in Congress, 30 percent, than they are in the population, 24 percent. Six percent of federal lawmakers are Jewish to their 1.7 percent imprint on the population. Mormon's are 2.6 percent of lawmakers, to their 1.7 percent of the population.
The most underrepresented faith group in the Pew study is unaffiliated, which claims no lawmakers, but 16 percent of the population. Five lawmakers don't specify their religion and one of those is Rep. Pete Stark, D-Calif., who is an admitted atheist, "a Unitarian who doesn't believe in a supreme being."
Faircloth of the Secular Coalition of America said, "The ultimate victory for all Americans would be that we simply don't talk about it."
Focus on the Family's Minnery said that kind of wholesale divorce between religion and politics cannot happen in the United States because politicians are more than happy, in many cases, to advertise their religion to voters.
"I say given the makeup of the people, politicians find it to their advantage to stress their connection to their faith," he said.
A study by Trinity College showed that 15 percent of Americans have no religion, but the number is far higher, 22 percent, among people 18-29. Having no religion is the fastest growing religious group in the United States, according to the Trinity study.
A Religious Litmus Test?
Minnery rejects the idea that there is a Christian litmus test in American politics.
"There is no litmus test, and the reason for that is that religion represents such a huge spectrum of belief," he said. "Many Christians have politically liberal views and many Christians have politically conservative. So it's not hard to find a home in that wide spectrum."
Proving the point, Minnery accepts that Obama is Christain but disagrees, he said, with him on many policy issues.
"We take at his word that he is a Christian, Minnery said. "That is between him and god. We are disappointed that he does not embrace more of the biblical principles such as the value of unborn life."
On this and many other issues, Minnery and Obama are divided, even though they share the same God.