Republicans in South Carolina, Malyerck said, appreciate Romney's support for the president, despite the fact that one of those bucking Bush was Lindsey Graham, the state's senior senator.

McCain's chief strategist, John Weaver, said the senator was focused on "broader national security issues and helping people get elected or re-elected in 2006 and not focused on what anybody may or may not be saying."

McCain makes decisions based on what he thinks is right, not to score political points, Weaver said. "I think that's a fair lesson for everybody, including Governor Romney."

Friday, Romney joined leading Christian conservatives at the 2006 Values Voter Summit, sponsored by the Family Research Council, an influential conservative Christian organization. Speaking to more than 1,400 people, Romney invoked the hugely popular evangelical pastor Rick Warren, expressed patriotic sentiments about family and country, and called for a federal constitutional ban on gay marriage. (McCain opposes such a ban.)

Romney also cited a 1913 Massachusetts law that has prevented same-sex couples from outside the state from marrying in the state if their marriage wouldn't be recognized at home. Romney proudly noted that because of that law, legalization of gay marriage in Massachusetts "has not affected the entire nation."

But he warned that if the Democrats win the governor's office in November, "that will change, I am afraid." (The Democratic nominee, Deval L. Patrick, has said he supports repealing the 1913 law, opening the possibility that the Legislature could wipe it from the books.)

McCain was given an invitation to speak at the summit but turned it down, said Connie Mackey, senior vice president of Family Research Council Action, the legislative action arm of the organization that sponsored the event.

Romney, Mackey said, is getting a surprisingly warm reaction from many on the right.

"There are people I would have thought would support other conservative hopefuls that are expressing real interest in seeing Romney move ahead," she said.

Other prospective GOP candidates scheduled to speak included Allen, Gov. Mike Huckabee of Arkansas, Sen. Sam Brownback of Kansas, and former House speaker Newt Gingrich.

Aside from competition from those potential contenders, Romney still faces obstacles in winning over conservative voters.

First, he has shifted his views on abortion in recent years. Though he now describes himself prolife, he said in 2002 that he supported the substance of Roe v. Wade. Also, Romney is Mormon, a religion that many evangelicals consider non-Christian.