One is the risk of alienating members — or potential members — who support the Democrats. That is significant for a church like the Latter-day Saints, which is already strongly associated with the GOP but doesn't want to turn off potential converts from either party.
The comparison to the 1960 Kennedy campaign is imperfect in significant ways, but worth pondering.
Catholics made up more than 20% of the American electorate in 1960, while Mormons are fewer than 2% today. Catholics may have faced prejudice, but they had the numbers to be a crucial pro-Kennedy voting bloc.
Mormons, by contrast, have significant strength primarily in states, such as Utah and Idaho, that are already reliably red in presidential contests. (Nevada, which Barack Obama won in 2008, is obviously less so.)
Still, there are notable similarities.
"I think it's a terribly reasonable analogue, because Catholics were opposed by many of the same groups … [and] for many of the same reasons," Givens said.
Evangelical Protestants, he said, questioned whether Catholics were more loyal to the Vatican or to their country, and even whether they should be called Christians. Mormons have faced similar questions in recent months, with one prominent evangelical pastor, Robert Jeffress of Dallas, calling Mormonism a non-Christian cult.
All that could be stirred up even more in a general election campaign. "I think we've only just begun to see the kind of anti-Mormon rhetoric that will emerge," Mason said.
Shaun Casey, author of "The Making of a Catholic President: Kennedy vs. Nixon 1960," said that Kennedy's Republican opponent, Richard Nixon, deployed a campaign aide who "distributed a staggering amount of anti-Catholic literature in the Protestant world."
"If you're a leader in Salt Lake City, you've got to be nervous about that," Casey said.