Last week, the Pew Forum released the results of its “Mormons in America” study, the broadest survey of Mormon attitudes ever conducted by an outside organization. The results made headlines, in large part due to the Republican front-runner status of Mitt Romney, a devout and life-long member of the Church of Jesus Christ of Latter-day Saints. Many accounts led with Mormons’ surprising perceptions of anti-Mormon prejudice: A whopping 46% of respondents said that Mormons face “a lot of discrimination” in modern America. Fewer Mormons said the same thing about discrimination against African-Americans (31%) and atheists (13%).

The specter of prejudice and persecution looms large in the Mormon myth. Under the leadership of founding prophet Joseph Smith, the early...