The question of whether or not Mormons are considered ‘Christians’ is sensitive and controversial.
I’m afraid they aren’t, as a group.
Catholic and Protestant churches believe that Mormons errantly revere the Book of Mormon and the teachings of LDS leaders and prophets such as Joseph Smith. To non-Mormons, the Latter-day Saint revelations are extra-biblical, even heretical, though in recent months a number of prominent Christian leaders and thinkers have defended Mormonism’s values.
Sure, they may have good values. They may even have “Christian” values, and some individuals may be Christians. But the organization and doctrines are not Christian. Why does this matter?
About one in five Republicans, or 18 percent, said they would not vote for a member of the Church of Jesus Christ of Latter-day Saints. … About the same proportion of independents said they would oppose a Mormon, while a larger number of Democrats, about 27 percent, said they were opposed, according to the poll.
For most people, the main problem with voting for Mormons is probably that they have “too much” values, rather than that they don’t have enough. The second most likely problem for Mormon politicians is the history of polygamy, racism, and heresy, along with a general cult-like image from a secular point of view.
Considering that only 26 percent of Americans identify as evangelical Christians, the raw numbers of voters who might not regard Mormons as Christians are not really significant. Sure, they matter from a leverage point of view, because their opinion carries a lot of weight with Republican power brokers. Moreover, if a lot of self-proclaimed moral authorities were to label Mormon politicians as not being morally authoritative, that would hurt their chances with social conservatives, including those who are not Christian. Enough “conservatives” are so pragmatic about their politics that they would ignore any question of Christian doctrine in order to promote their pet legislative issues.
However, the basic premise of this controversy is stupid. The president of the United States, like the kings of ancient Israel, cannot function as a high priest. Even if he were head of the Church of America, that would mean nothing for individual believers or local congregations. I absolutely reject the model of institutionalized religion promoted in Europe and Great Britain, such that if that were the only “church” option in America, I would be a functional atheist. The nation-state cannot be sanctified by the church. Therefore, it doesn’t matter what particular doctrine the president holds to.
However, it does matter politically whether the president is rational and what issues he wishes to push. There are some religious viewpoints which are simply not defensible rationally, and there are others which will simply never be accepted as trustworthy by the general population, much less other people in power. Traditionally, presidents have succeeded best with a moderate, wishy-washy, generic civic religion that includes occasional cryptic biblical allusions and the use of the word “God.” I have no doubt that a Mormon could summon that much blandness, if only he could separate himself from the cult associations that Mormonism historically has had.