With Mormons Jon Huntsman and Mitt Romney among the top contenders for the 2012 GOP presidential nomination, a new documentary explores their religion and how it plays out in their political careers. “A Mormon President,” premiering next month, touches on America’s first Mormon presidential candidate, Joseph Smith, his assassination and the long-running rift between Mormonism and other faiths. Adam Christing, the film’s producer, spoke with The Hill about the challenges facing a Mormon candidate, prominent Mormon leaders in today’s government and what he identifies as an “anti-Mormon prejudice in this country.” Q: With Jon Huntsman and Mitt Romney running for president, what do voters need to know about the history of Mormonism?