COLLEGE STATION, Texas - His campaign at a crossroads, Republican Mitt Romney said today that his Mormon faith should neither help nor hinder his quest for the White House, and he vowed to serve the interests of the nation, not the church, if elected president.

"When I place my hand on the Bible and take the oath of office, that oath becomes my highest promise to God," Romney said in a speech that explicitly recalled remarks John F. Kennedy made in 1960 in an effort to quell anti-Catholic bias.

After declining for months to address the issue of his Mormonism directly, Romney switched course as polls showed widespread unease about his religion - and showed him losing his once-sizable lead in the opening Iowa caucuses to Mike Huckabee, a Baptist minister and former governor of Arkansas.

Romney said some believe that a forthright embrace of his religion would "sink my candidacy. If they are right, so be it. But I think they underestimate the American people. Americans tire of those who would jettison their beliefs, even to gain the world.

"Let me assure you that no authorities of my church, or of any other church for that matter, will ever exert influence on presidential decisions," he pledged.

"If I am fortunate to become your president, I will serve no one religion, no one group, no one cause and no one interest. A president must serve only the common cause of the people of the United States."

Mormons believe that authentic Christianity vanished a century after Jesus and was restored only through Joseph Smith, who founded the religion and is viewed as a prophet. Smith revised large sections of the Bible in the 19th century, an act of heresy in the eyes of Protestant and Roman Catholic leaders.

Romney mentioned the word Mormon only once, and Huckabee not at all in his speech at the George H.W. Bush Presidential Library. In speaking frankly about his beliefs, he hoped to reassure other Christians about his intent.

"I believe that Jesus Christ is the Son of God and the savior of mankind. My church's beliefs about Christ may not all be the same as those of other faiths," he said, adding that these differences are "not bases for criticism, but rather a test of our tolerance."

Steve Scheffler, president of the Iowa Christian Alliance, said: "I think he did what he thought he needed to do to address concerns about whether he might use his particular faith as the basis for his decisions as president."

James Dobson, founder of Focus on the Family, called Romney's speech "a magnificent reminder of the role religious faith must play in government and public policy. Whether it will answer all the questions and concerns of evangelical Christian voters is yet to be determined, but the governor is to be commended for articulating the importance of our religious heritage as it relates to today."

Among the critics was Costas Panagopoulos, a political science professor at Fordham University. "Make no mistake about it, this was a political speech. Romney sounded like he is running for pastor-in-chief rather than commander-in-chief."

Romney's rivals generally steered clear of comment on the speech, but Huckabee told NBC's Today show that Romney's religion has no bearing on whether he would make a good president. "It has nothing to do with what faith a person has, it's whether or not that person's life is consistent with how he lives it," Huckabee said.

While Romney has been subject to some leafletting and phone calls pointing to religious differences between his faith and others', he has faced little outright religious bigotry or questions on the campaign trail. Yet, in an AP-Yahoo poll last month, half said they had some problems supporting a Mormon candidate.

Romney sought to allay those concerns by confronting them yesterday. And he chose a presidential library, with a backdrop of 10 flags and the presidential seal, for his speech.

Former President Bush introduced him, noting his connection to Romney's late father, former Michigan Gov. George Romney. "He's certainly one of my mentors when it comes to points of light," said Bush, who enacted an initiative while president called, "Thousand Points of Light."

That said, Bush had no endorsements. "I simply have too much respect for all of the candidates."