The Republican Party launched in 1854 as an anti-slavery party and quickly seized on growing concern with Mormons in the Utah Territory taking on multiple wives. The GOP's first party platform in 1856 took direct aim at polygamy, placing it in the same sinister frame as slavery in the hope of cultivating the votes of Christians wary of the spread of these dual threats to the republic. "It is both the right and the imperative duty of Congress to prohibit in the Territories those twin relics of barbarism — polygamy, and slavery," the party declared as it emerged on the national stage for the first time.
We sometimes forget, I think, how big a step forward it is to have a Catholic and a Mormon vying for the GOP nomination. Unthinkable not so long ago. It's not that far removed from having a bi-racial dude and a woman vie for the Dems last time around.