Last week, Huckabee sought to exploit Romney's weaknesses — his Mormon faith and his reversal on abortion as well as shifts on other issues — by running a TV ad in Iowa that emphasizes his own religious beliefs. The ad doesn't mention Romney but clearly targets him.

"Faith doesn't just influence me. It really defines me. I don't have to wake up every day wondering what do I need to believe," Huckabee says in TV ad. "Let us never sacrifice our principles for anybody's politics. Not now, not ever."

But Huckabee, in an interview on ABC's "This Week," took a pass when asked if Mormonism contradicts the central teachings of Christianity.

Romney, for his part, sought Friday to strengthen his own support among religious and social conservatives, meeting with members of the grass-roots network the Iowa Christian Alliance in Dubuque, Iowa.

"I am pro-life. I am pro-family," Romney told them. "If I am the president of the United States — and frankly even if I'm not — I will work hard and tirelessly to preserve marriage as an institution, which is fundamental to the preservation of this great land."

How he should deal with questions about his faith has divided his campaign advisers.

Some advisers had suggested that he give the speech touching on his beliefs and clarifying the impact of his faith on his governmental decisionmaking. Those advisers privately said that Romney would benefit from such a speech because Mormons pride themselves on the separation of church and state, as well as a tolerance for all religions.

Until now, Romney has chosen an incremental approach supported by other advisers in which he answers questions about his faith during town hall meetings or media interviews. Those advisers' concern was that discussing the tenets of the Church of Jesus Christ of Latter-day Saints would draw too much attention to his religion.