(AP Photo/Jae C. Hong)

With his much-hyped Liberty University commencement address delivered this past Saturday morning, Mitt Romney performed a rare feat in American presidential politics. He lived up to expectations. And if the praise the former governor has already received from the nation’s leading evangelicals is any indication, he might have even surpassed them.

With a speech full of the buzzwords that resonate with Christian conservative voters, many of whom have been wary to back a Mormon, and the former governor of liberal Massachusetts, for president, Romney sought to convince them that they could count on him to fight for the causes they hold most dear. Family Research Council President Tony Perkins described the speech as “an acknowledgment that the issues that social conservatives and evangelicals care about are important issues to Gov. Romney.” Gary Bauer, the chairman of the Campaign for Working Families, called Romney’s performance “a grand slam for millions of Americans who care about family, faith and freedom.” Liberty alumnus, trustee, and senior Romney advisor, Mark DeMoss (who introduced Romney at Liberty) told me that, following the speech, he received numerous email and text messages praising the candidate. He said “based on the reaction in the stadium [and] comments from those who attended a luncheon with him afterwards,” Romney was “well received.”

For the “values voters” that Perkins, Bauer, and DeMoss represent, the highlight of the speech was Romney’s unequivocal declaration that “marriage is between one man and one woman,” a line that the more than 34,000 people in attendance rewarded with an extended standing ovation.

Following the announcement earlier in the week that President Obama now supports same-sex marriage, it came as little surprise that gay marriage was a focal point of Romney’s visit to Liberty. But what did surprise many political observers was that Romney made reference—though indirect—to his Mormon faith. While he acknowledged that “there are so many differences in creed and theology” between his own Mormon faith and that of evangelical Christianity, Romney rejected the idea that these communities cannot “meet in common purpose.” He continued, “Surely … we can meet in service, in shared moral convictions about our nation stemming from a common worldview.”

Romney’s message to Liberty, and to the conservative Christians watching around the country, was that because they shared “a common worldview” about the nation’s most elemental cultural institution—the monogamous, heterosexual family—they can tolerate a Mormon for president, and can form a coalition of “values voters” that will help him defeat the pro-gay marriage Obama.

But even in his highest aspirations for the speech, Romney did not expect to convince conservative evangelicals to express religious tolerance for Mormonism.

And for good reason. Conservative Christians like the Rev. Robert Jeffress label Mormonism “a theological cult” because of the doctrinal differences still present between Mormons and evangelicals. At Liberty University, seminary and graduate school applicants must fill out a questionnaire that explicitly states that the Quran and the Book of Mormon are not books of “divine revelation.” In another of the questionnaire’s statements, students must acknowledge that they affirm the evangelical, ontological conception of God, and reject the Mormon one. “God became man only in the incarnation of Jesus Christ as the God-man,” the statement reads. “The creator God is not a man raised to divine status,” a simplified, but more or less accurate description of the Mormon conception of “Heavenly Father.”

Evangelical Christians cannot tolerate Mormonism theologically because of the core doctrines that the Church of Jesus Christ of Latter-day Saints (LDS) hasn’t changed. But ironically, evangelicals can tolerate Mormonism politically (e.g. they can endorse Romney for president, as Jeffress recently did; they can invite him to give a commencement address at Jerry Falwell’s Liberty University) because the LDS Church has changed one core doctrine: the Mormon conception of marriage.

Not surprisingly, on Saturday Romney made no mention of his faith’s own historical struggles with the United States’ government over polygamy. Celestial (or plural) marriage, as the 19th century Saints called it, was fundamental to the Mormon faith; they argued that their right to practice it was a religious liberty (the same liberty that Romney called on Saturday “the first freedom in our Constitution”). To protect polygamy, the Saints were willing to go to war with America, to allow the imprisonment of many of its leading church officials, and to endure a half-century’s worth of anti-Mormon ridicule from the American media. In 1856, Romney’s own Republican Party’s first presidential platform resolved, “to prohibit in the Territories those twin relics of barbarism—Polygamy, and Slavery.” The American body politic only began to accept Mormonism, and accept Utah as a state when Mormons abandoned their own non-traditional views of marriage.

This is his faith’s historical struggle with theological conceptions of marriage and the conflicts they created in the American political arena. But this is also Romney family history. After the LDS Church issued the 1890 “Manifesto,” which officially ended polygamy, church officials sent a select group of Mormons across the Mexican and Canadian borders to continue the practice. Included in this group was Miles Park Romney, Mitt Romney’s great-grandfather who, with his four wives, relocated to northern Chihuahua. It was here where Mitt’s own father, the future governor of Michigan and 1968 hopeful for the GOP nomination for the presidency, was born.   

History (both that of the Romney family and their church) teaches us Mormons have made the transition to political acceptability due to the changes they were willing to make to their own theology of marriage.

But on Saturday, Romney wanted to emphasize America’s future, not history. He told the audience, “If we take the right course,”—a part of which is creating a coalition of like-minded believers to elect him president—“we will see a resurgence in the American economy that will surprise the world, and that will open new doors of opportunity for those who are prepared as you are.”

In a significant way, the success of this coalition will ironically be built around the idea that marriage is morally, and should be legally, “a relationship between one man and one woman,” a theological view that Romney’s 19th century spiritual and biological ancestors did not share.

But the question is, will this coalition hold until Election Day? After all, there remains one core theological difference between Mormon and evangelical conceptions of marriage. Romney’s faith teaches that marriage is “for time and eternity.” Evangelical marriages—“until death do us part”—aren’t promised to be that long.

Max Perry Mueller is associate editor of Religion & Politics.