Is there an unwritten religious litmus test for the U.S. presidency? Do voters require candidates to be “not just religious, but acceptably religious”? Yes, say Northwest Nazarene University professors Steve Shaw and Darrin Grinder.

"Al Smith's cabinet" cartoon shows Smith as waiter to Pope, cardinals in the White House

If they are right, will Mitt Romney’s Mormonism doom his bid for the presidency? After all, Catholicism was blamed for New York Gov. Al Smith’s loss to Herbert Hoover in 1928. Smith was denounced by vocal Southern Baptists and German Lutherans who were convinced he would take orders from the Vatican.

Such fears prompted John F. Kennedy to make a historic Sept. 12, 1960, speech to the Greater Houston Ministerial Association. He pledged he would resign if faced with a conflict between the Constitution and his beliefs.

John F. Kennedy made no attempt to hide his faith

It was speculated that Romney might make a similar declaration in his address to the late Jerry Falwell’s Liberty University commencement crowd on May 13, but he did not.

A “lingering suspicion among evangelicals — a key Republican constituency — about Romney’s Mormon faith,” writes David Gibson of the Religious News Service, “has led some to suggest that Romney needs to make a speech about his Mormonism along the lines of John F. Kennedy’s defense of his Catholicism to Protestant leaders during the 1960 campaign. So could Romney pull a Kennedy? Should he?”

Mike Huckabee, a Southern Baptist minister who sought the GOP nomination in 2008, told Fox News after Romney lost the 2011 South Carolina primary it was time for Romney to address his Mormonism – that such a speech would “sort of dismiss it, make it less important.”

But it’s not only the evangelical right that has questions. Sally Denton of the left-of-center magazine Salon cites “the White Horse prophesy” by Mormon founder Joseph Smith. He ran for president in 1844 as an independent commander-in-chief of an “army of God” advocating the overthrow of the U.S. government in favor of a Mormon-ruled theocracy. Challenging Democrat James Polk and Whig Henry Clay, Smith prophesied that if the U.S. Congress did not accede to his demands that “they shall be broken up as a government and God shall damn them.” Smith viewed capturing the presidency as part of the mission of the church and predicted the emergence of “the one Mighty and Strong” – a leader who would “set in order the house of God.”

Death masks of Mormon founders James and Hyrum Smith

Out of that, writes Denton, grew the “White Horse Prophecy,” which she describes as “a belief ingrained in Mormon culture and passed down through generations by church leaders.”

Former candidate for Nevada governor Michael Moody writes in his memoir that the prophecy “motivated me to seek a career in government and politics” because he felt he had been divinely directed to “expand our kingdom” and help Romney “lead the world into the Millennium.” Now a critic of the Mormon church, Moody says he was indoctrinated with the White Horse Prophecy.

“We were taught that America is the Promised Land,” he said in an interview.”The Mormons are the Chosen People. And the time is now for a Mormon leader to usher in the second coming of Christ and install the political Kingdom of God in Washington, D.C.”

Will such talk put off voters?

Ronald Reagan

“Pundits and scholars, rabbis and bloggers, have repeatedly posed the question during Romney’s run: Is a candidate’s religion relevant?” writes Denton. “With a startling 50 percent increase of recently polled American voters claiming to know little or nothing about Mormonism, another 32 percent rejecting Mormonism as a Christian faith, a whopping 42 percent saying they would feel ‘somewhat or very uncomfortable’ with a Mormon president, and a widespread sense that the religion is a cult.