WASHINGTON — The Southern Baptist Convention Web site categorizes The Church of Jesus Christ of Latter-day Saints as a "cult" that is "radically" different from historic, biblical Christianity.

A faith guide issued by the influential Christian right group Focus on the Family declares that "God cannot be identified . . . with the Mormon religion's notion of god." And each year, evangelical organizers behind the National Day of Prayer bar Mormons from speaking at their proceedings.

As Gov. Mitt Romney mulls a race for president in 2008, his strategists expect their "family values" candidate — who opposes gay marriage, abortion and some forms of embryonic stem cell research — to find a natural base of support among religious conservatives. "As Mitt has traveled the country and tested the waters, he's gotten very strong responses, including from religious conservatives," said Michael Murphy, a political consultant who advises Romney.

But an examination of the views of powerful Christian right groups suggests that, even as some of these voters might appreciate Romney's lifelong commitment to his church, the governor's LDS Church faith could become an obstacle for others among this same group, who make up a large and vocal segment of Republican primary voters.

A Romney run for president would test the unity of a Christian right voting bloc that for the past five years has demonstrated remarkable solidarity on issues ranging from sexuality and family life to President Bush's first choice as Supreme Court justice. An estimated 40 percent of Republican primary voters are conservative Christians. Romney strategists are reluctant to speak about a potential presidential run until the governor has made up his mind, but they remain attuned to how Romney's faith plays with these voters. Last March, the governor invited Southern California evangelical pastor Rick Warren to breakfast in Cambridge after reading his bestseller, "The Purpose Driven Life."

Protestant evangelicals commonly overlook vast theological differences to form political alliances with people of other faiths, particularly conservative Catholics and Jews. But the LDS Church, in particular, faces an activist opposition from a faction of conservative Protestants.

Most anti-Mormon activists come from "the right wing of the evangelical community," said Robert L. Millet, professor of religion at Brigham Young University. The Southern Baptists are a key piece of the right wing, which also contains a range of Christian fundamentalists. The early Mormons faced violence and persecution for their religious beliefs and practice of polygamy, which the church has long since outlawed and now vigorously condemns. Today, expressions of anti-Mormonism manifest themselves on Web sites, in books and documentaries, and through invective sometimes hurled by Christian fundamentalists at temple-goers in Salt Lake City.