When it comes to American exceptionalism, Mitt Romney is going all in.

His book “No Apology: The Case for American Greatness” is a love song to the idea that this country merits “the protection of Providence” and has a singular “calling” to be a beacon for freedom. A major theme for him on the campaign trail is the nation’s divine destiny, a heritage Romney said has made him “stand a little taller, a little straighter” when overseas.

But what Romney doesn’t say is that, for followers of his made-in-America religion, Mormonism, exceptionalism isn’t political metaphor. It’s theology.

The faith’s sacred text, the Book of Mormon, describes the United States as “a land of promise . . . a land which is choice above all other lands.” It describes Jesus coming down from heaven, to America, and teaching to people there. Joseph Smith, Mormonism’s founder and prophet, quotes God as saying that he established the U.S. Constitution. Mormons’ Garden of Eden is in Missouri. Their version of the hajj begins in Upstate New York and ends in Illinois.

Other post-Reagan candidates may passionately preach beliefs like Romney’s, but he’s the only one who can say American exceptionalism is his religion.

Except he doesn’t.

Romney, a former bishop and devout Mormon, speaks only subtly about his faith — perhaps to protect his privacy, perhaps to protect his political standing in an era in which many Americans are wary of and ignorant about Mormonism. In his faith, the United States is the land God picked to restore Christianity. But Romney doesn’t say what that religious exceptionalism means to him.

Mormon experts who closely follow Romney can’t name a time he has commented on how this motif in his faith has shaped his political views. His book doesn’t address it, and his campaign spokeswoman didn’t return requests for comment.

Romney has been general about where his faith meets that of others. On Saturday at Liberty University, the country’s largest evangelical university, he told graduates: “We can meet in service, in shared moral convictions about our nation stemming from a common worldview.”

Romney’s reticence on the subject of God and country makes him a typical Mormon. Persecuted by the government in the 1800s, Mormons grew wary of how to merge their faith with their love for the land it blesses.

At the height of tensions over polygamy, when Congress effectively outlawed it in the 1800s, Mormons went to the Supreme Court to argue that the practice was protected under the First Amendment. If polygamy were forbidden, they said, the nation would be abandoning God and his desire for religious freedom. Once Mormon leaders decided to officially give up polygamy in 1890 so Utah could become a state, Mormons slipped surprisingly easily into patriotism, largely because they have a scriptural infrastructure to support it. Leaders gave exceptionalism a face-lift; in the early 1900s, Smith’s nephew Joseph F. Smith promoted the purchase of pieces of American real estate mentioned in Mormon history to create the popular pilgrimage-like trip, now called the Church History Tour.

“It’s an attempt to return the identity of the church and to leap over this awkward history of polygamy and to revive this founding story. To draw Mormons away from thinking of themselves as persecuted,” said Matthew Bowman, a historian of American religious history and Mormonism.

After that, Mormons largely adopted the Book of Mormon’s view that the United States is a promised land and that Mormons have a duty to obey God and keep the country on the right track.

“If you are an America-hater, you’d have a hard time functioning in the LDS [Latter-day Saints] church,” said David Campbell, a political scientist at the University of Notre Dame.

Recent Mormon leaders continued Smith’s prediction that “the New Jerusalem” would be built on what he called “the American continent.” That’s traditionally been understood to be a reference to a site in Missouri. Ezra Taft Benson, President Dwight D. Eisenhower’s agriculture secretary and later a president of the Church of Jesus Christ of Latter-day Saints, spoke of the nation as “the Lord’s base of operations.” J. Reuben Clark, a Mormon church leader and undersecretary of state in the 1920s, said the Constitution and “the free institutions which it creates are perpetuates are God-given.”

Exceptionalism also played out in radical forms. In the mid-1900s, a strain of what Bowman calls “strident hyper-patriotism” emerged among Mormons (still embodied, he says, by Glenn Beck) that resembles libertarianism. Even if they aren’t Beck-ites, most Mormons — like Romney — have a strong, theology-rooted preference for a small government.

Mormons believe human souls existed before the world was created, and two works of scripture tell the story of a conversation God has with all his spirit children, including Satan and Jesus. God lays out his plan to create the universe, and human bodies that will allow the souls to make decisions. Satan suggests forcing everyone to make only right decisions so no souls are lost. God rejects that idea in favor of free will. Satan is cast out of heaven, and Jesus volunteers to come to Earth and be killed for the sins of free people (who sometimes make mistakes).

Seventy-four percent of Mormons say they identify with or lean toward the Republican Party, the highest percentage of any faith group. That devotion isn’t explained only by exceptionalism, and decades ago Utah was more of a swing state. But like other religious conservatives, Mormons were galvanized by Roe v. Wade and the feminist movement.

Contemporary Mormonism is intertwined with contemporary conservatism in several major ways. “It makes it hard to untangle,” Campbell said, including when you listen to Romney. “When he talks about America’s special place in the world, all of that resonates with his Mormonism, but those very same statements in the same language will resonate with conservatives who aren’t Mormon.”

“America the Beautiful” and “The Star Spangled Banner” are in Mormon hymn books and are sung around the Fourth of July. However, to separate the sacred from the patriotic, Mormons — unlike most other faith groups — typically don’t allow their houses of worship to be used for voter registration. The Sunday before state and federal elections, worshipers are reminded that the Mormon Church doesn’t endorse candidates and to vote their conscience.

In a globalized world, being an American evangelistic faith can pose a marketing problem. While Smith included among his 13 fundamental “Articles of Faith” the belief that the Earth’s renewal required the “literal gathering” of the tribes of Israel on the American continent, the wording got tweaked as Mormons took their faith worldwide. In the 1950s, Mormon President David O. McKay reversed a century of encouraging converts to move to the promised land of America and said Zion was not a place but a way of life. And speeches at the semiannual General Conference, a major meeting of church leaders, have mostly been purged of overt nationalism.

Phil Barlow, an American religious history professor at Utah State University, said Mormon American exceptionalism is complex. In the Book of Mormon, he writes in an upcoming essay for the Review of Faith and International Affairs, “America is a land of promise — until it’s not.” The book introduces various promised lands and people who “become unchosen” if they “lose their moral fiber.”

Barlow and other experts see Mormon exceptionalism as a bipartisan belief, applicable to a Romney-style focus on economic and military dominance or an Obama-like focus on democracy and hope. “One could extract from Mormon history, culture, and scripture reasons for supporting either man’s understanding of what makes the nation special,” Barlow writes.

That said, Barlow knows the candidate has left this connection murky. A top aide to Romney when he was a bishop in Massachusetts, Barlow said he was unaware of Romney ever speaking on Mormon ideas of American exceptionalism.

In Romney’s silence on the spiritual roots of his exceptionalism, Bowman sees a typical Mormon. “Mormons emphasize practice, not doctrine,” he said. “I doubt he’s thought deeply about theology because that’s not how Mormons are.”

But there might be another reason.

“If he did get up and say, ‘In my work of scripture, this is a land of promise,’ I think that would go over fine with most Republican audiences. If he said, ‘The Garden of Eden is in Missouri,’ that would strike people as odd.”

Michelle Boorstein is a religion reporter for The Washington Post.

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Romney is the right man for America. George Romney, that is.

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Michelle Boorstein is the Post’s religion reporter, where she reports on the busy marketplace of American religion.