LYNCHBURG, Va. - Mitt Romney, needing badly to stir momentum among skeptical evangelical Christians vital to his presidential hopes, told a polite audience Saturday at Liberty University, an influential Christian school, that he shared and deeply respected their values.

"People of different faiths, like yours and mine, sometimes wonder where we can meet in common purpose, when there are so many differences in creed and theology," said Romney, whose Mormon religion has been criticized in some evangelical circles.

"Surely, the answer is that we can meet in service, in shared moral convictions about our nation stemming from a common worldview."

Romney spoke at the school's commencement, and he got his most enthusiastic response when he reiterated his view that "marriage is a relationship between one man and one woman." President Obama earlier in the week said he supported same-sex marriage, a surefire way to galvanize evangelicals and other social conservatives to work against his reelection.

Romney seized the chance to show he was behind them, as his remark got one of the day's three standing ovations; the others, consisting of brief, subdued applause, came at the start and end of his talk.

The presumptive Republican presidential nominee needs this crowd, particularly in this pivotal state. Throughout the primary and caucus season, he did poorly among evangelical Christian voters like those who support and attend this school, which bills itself as "training champions for Christ since 1971."

It was founded by the late Rev. Jerry Falwell, the leader of the Moral Majority, and emerged as a political force during Ronald Reagan's 1980 presidential run.

Romney had three goals Saturday: To assure everyone present that he shared the audience's values, that he'd lived a good, moral life, and was running for president to heal the ailing economy.

"Central to America's rise to global leadership is our Judeo-Christian tradition, with its vision of the goodness and possibilities of every life," he said.

Romney dwelled heavily on his own family. "I have never once regretted missing any experience or opportunity in business in order to be with my wife and five sons," he said solemnly.

"In this life, of course, the commitments that come closest to forever are those of family. Maybe you've heard that [wife] Ann and I have a pretty large family, and I'm sure glad I like having grandchildren, because every time I turn around, there's more of them."

Romney, who's been married for 43 years, has 18 grandchildren.

Though the festive crowd was generally supportive, many still expressed reservations about Romney. Last month, the Liberty Champion, the student newspaper, wrote in a commentary: "Mitt Romney was announced as Liberty's 39th commencement speaker, great - but he is a Mormon."

Many conservative Christians remain dismayed by his center-right record as governor of Massachusetts from 2003 to 2007. He was then an abortion-rights supporter; today he stresses his firm opposition. He signed state health-care legislation viewed as a model for the 2010 federal law that requires nearly everyone to obtain coverage in 2014 or face a penalty. Conservatives deride the federal law as "Obamacare."

"He's the lesser of two evils," said Kristine Funk, a Manchester, N.H., preschool teacher present at the graduation. "I don't agree with a lot of his positions, but I can't vote for Obama."