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.

That's not to say Romney can't attract votes from evangelical Protestants by advertising his success running the 2002 Winter Olympics in Salt Lake City, his experience running a major state, and his increasingly conservative views on social issues such as abortion — the three building blocks of his potential candidacy, according to advisers and other political leaders.

"There are key doctrinal differences between Mormons and Baptists — and most other evangelicals," said David S. Dockery, board chairman of the Council for Christian Colleges and Universities. "But I don't see that that would be an issue (in a presidential bid) because he would share many of the same views on political and cultural issues, especially related to life and family, the economy and the environment."

But for some Protestant evangelicals, casting a vote for Romney will be a hurdle, particularly if they like his stands on social issues but have concerns about his church's teachings.

"Evangelicals are going to have a conundrum on their hands with that one," said the Rev. Greg Johnson, a Utah pastor who co-chairs Standing Together Ministries, a national effort to improve relations between the faiths.

Eric Fehrnstrom, the governor's spokesman, said Romney will make a decision this fall whether to run for re-election in Massachusetts. If he declines, he is widely expected to throw his hat into the presidential ring.

The LDS Church boasts a range of high-level political figures; its 17 members of Congress are mostly Republican, but also include Senate Democratic leader Harry Reid, Democrat of Nevada. The church is known for a strong network that Romney can draw on for fund-raising and support.

But political power doesn't guarantee an open door to Washington's religious social world of Bible meetings and prayer groups, said John M. Haddow, a member of the LDS Church and a Washington attorney who once served as Hatch's legislative director and remains close to a number of leading Mormon political figures.

Last year, Haddow protested with calls to friends on Capitol Hill after reading news reports that members of the LDS Church weren't permitted to speak at National Prayer Day events organized by evangelicals associated with the wife of Rev. James Dobson, the politically influential Christian psychologist and leader of the activist group Focus on the Family. "I said, 'It's National Prayer Day (and) you decide who can pray and who can't?' " Haddow recalled asking.