Oct. 8, 2007 -- If religion is a top-tier issue for Republican voters, somebody forgot to tell the party's top contenders.
Among the White House hopefuls, the Democratic candidates are talking more about their faith -- and engaging in more early outreach to religious voters -- than Republicans are.
It marks a major shift from 2000 and 2004, when George W. Bush peppered his speeches with religious references and talked openly about his personal beliefs.
"It is amazing: You have Democrats as evangelicals, and Republicans behaving as secularists," said David Kuo, who was deputy director of President Bush's faith-based office during Bush's first term.
"In running away from Bush, it's as if the Republicans have decided they can't talk about religion," Kuo said. "They are treating the electorate essentially as a secular electorate, which is just fascinating."
Connecting With Religious Voters
The dynamic could harm Republican turnout in a year that the GOP can hardly afford to lose any of its base voters. The shift has prompted concerns by some Republicans that conservative and religious voters could choose not to vote next fall.
While Bush found a way to connect with religious voters by talking about his faith in a highly personal context, the current crop of Republican contenders is not nearly as comfortable talking up faith, said Clyde Wilcox, a Georgetown political science professor and author of "Onward Christian Soldiers? The Religious Right in American Politics."
"What Bush was especially talented at doing was talking about religion in a way that unified people by just saying how religion made him feel," Wilcox said.
"There's no Republican candidate that can do the unifying message the way that Bush does. ... And that makes it hard for evangelicals to really get excited and turn out."
Giuliani Demurs When Asked About Faith
The GOP reticence to talk religion stems in part from the backgrounds of the major candidates.
The national front-runner, former New York mayor Rudolph Giuliani, once aspired to be a priest, but after two divorces and various personal dramas, he demurs when asked on the campaign trail about his faith.
Some social conservative leaders have even threatened to support a third-party candidate if Giuliani gets the Republican nomination, citing his support for abortion rights and gay rights.
Former Massachusetts Gov. Mitt Romney is trying to become the nation's first Mormon president, and is deeply religious himself. But while he's been asked pointed questions about the tenets of his religion, he has so far resisted calls for a major public address laying out how his faith might affect the way he'd govern.
"He has a good bit of work to do to try to overcome that skepticism about his faith," said John C. Green, a senior fellow at the Pew Forum on Religion and Public Life.
McCain: 'Agents of Intolerance'
Former Tennessee Sen. Fred Thompson was seen as the great hope of many religious and conservative leaders before he got in the race last month. But he's been something of a disappointment as a candidate, and he conceded shortly after declaring his candidacy that he doesn't attend church regularly.
James Dobson, one of the nation's most politically influential evangelical Christians, has said he would not support Thompson for the Republican nomination and has accused him of being wrong on issues dear to social conservatives.
Arizona Sen. John McCain raised eyebrows this month by saying that he considers himself a Baptist after letting himself be publicly identified as an Episcopalian throughout his career in public life.
McCain has also said he's not comfortable talking about his personal faith -- and he may never live down his famous description of Jerry Falwell and Pat Robertson as "agents of intolerance" during the 2000 campaign.
Other Republican candidates do talk comfortably and openly about their faith -- notably former Arkansas Gov. Mike Huckabee and Kansas Sen. Sam Brownback. But their candidacies have failed to catch fire.
When Republicans do talk about faith these days, it sometimes gets them in trouble. McCain recently drew heat from Jewish and Muslim groups by saying that the United States was founded on "Christian principles," and that he could not see himself supporting a Muslim for president.
He also said last week that he's not sure whether Mormons are Christians, though he later added that he takes Mormons -- like Romney -- at their word when they say they are Christians.
Democratic Candidates Speak Openly About Faith
Democrats have been less circumspect about their religion on the campaign trail. The three leading candidates -- Sens. Hillary Clinton, D-N.Y., and Barack Obama, D-Ill., and former senator John Edwards of North Carolina -- all talk openly about their religious beliefs and have launched aggressive efforts to reach voters for whom faith is a top issue.
Obama's campaign has organized 27 "faith forums" in Iowa and New Hampshire so far this year -- gatherings where between 35 and 70 religious voters convene to discuss connections between their faiths and their politics.
He has launched a South Carolina initiative called 40 Days of Faith and Family, which includes gospel concerts and Bible study programs organized by his presidential campaign.
"We're changing the meaning of what it means to be a 'values voter' in this country," said Joshua DuBois, the Obama campaign's national director of religious affairs. "All of these things have a moral component."
'Obama: 'I Can Be an Instrument of God'
On Sunday, Obama spoke about how it wasn't until after college that he became more religious.
"I cast about after college to see how I could participate in building God's kingdom," Obama told a crowd of nearly 5,000 at the Redemption World Outreach Center in Greenville, South Carolina.
After three years working with churches as a community organizer in Chicago, Obama said he accepted Christianity.
"Through that interaction with the church I accepted Jesus Christ in my life ... I can be an instrument of God they same way all of you are," he said.
Clinton has said that she probably could not have gotten through her marital troubles without relying on her faith in God.
"I am very grateful that I had a grounding in faith that gave me the courage and the strength to do what I thought was right, regardless of what the world thought," Clinton said in June during a forum sponsored by the liberal Sojourners/Call to Renewal evangelical organization, where the three leading Democratic presidential candidates talked about faith and values.
"I'm not sure I would have gotten through it without my faith," Clinton said in response to a question about how she dealt with the Monica Lewinsky scandal.
Former North Carolina Sen. John Edwards admitted during the forum that for many years, he strayed from the church. But he said his faith roared back when he lost his teenage son to a car accident.
"When Elizabeth and I lost our son, we were nonfunctional for some period of time and it was the Lord that got me through that," Edwards said.
Fighting for 'Values-Voter'
Republicans, of course, aren't going to concede religious voters to the Democrats. But the Democratic Party has made it clear that they will fight for voters with deep religious convictions, regardless of whom those voters supported in the past.
"Democrats are reclaiming the idea that yeah, they have values too, they're just slightly different values than the Christian Right," Wilcox said. "They're going to fight for the phrase 'values voters' this time."
With reporting by ABC News' Sunlen Miller.