The conversion of blacks in this country has been a challenge, given the church’s turbulent history of excluding people of black African descent. Until 1978, black men were not allowed to become priests or bishops; dark skin was considered a biblical curse. During the 1960s, when Mitt Romney’s father, George, made civil rights a personal priority during his time as a Republican governor of Michigan, his progressive views put him at odds with church doctrine.

Over the last decades, however, there has been an aggressive campaign to diversify, and racism in the church — which was itself once powerless and persecuted as a cult — has been repeatedly denounced.

“I feel a definite sense of pride in the U.S.A. that we have a Mormon candidate and black candidate,” said Catherine Spruill, who lives in a suburb of Salt Lake and is mixed-race like Mr. Obama and Mormon like Mr. Romney. “I feel pride for my people, because America picked that.”

There is even a black Mormon Congressional candidate, Mia Love, who will soon be on the ballot in Utah. She is running as a conservative Republican for the newly created Fourth District, which includes part of Salt Lake County. A campaign video describes her in these terms, among others: “mother, mayor, leader, gun owner.”

With the larger tent has come a more diverse array of political ideologies and expressions in a church culture that has been known for its strict hierarchy and members’ adherence to authority and rules, for instance the prohibitions on caffeine and alcohol. Of more than a dozen black Mormons interviewed for this article across the country, eight were Democratic-leaning Obama supporters, two were undecided, and two others said they were committed to voting for Mr. Romney.

“With respect to Romney being a Mormon, bless his heart,” said Tracie J. Walker, 48, of Washington. “I think he’s a strange character. He got confused by money, I think. So he doesn’t understand reality today.”