FRED DE SAM LAZARO, guest anchor: The presidential election campaign is in full swing, and candidates from both parties were swinging through pivotal states in the so-called Bible Belt this week. Kim Lawton has this round-up.

KIM LAWTON: Religion has been high on the agenda this campaign season, as candidates visit churches, talk about their personal beliefs, and rack up religious endorsements -- all in an effort to mobilize faith-based voters. In a free-for-all primary season where no incumbent president is running, religion can be one important rallying point.

Professor LAURA OLSON (Political Science Department, Clemson University): What we see is these candidates very much going out and saying, "I need to reach out to that constituency. I need them on my side, because I know that they're quite cohesive politically, and I know that if I want to live to fight another day, I need to have these people with me."

LAWTON: But there's also sharp debate over the proper role faith should play.

Reverend C. WELTON GADDY (Interfaith Alliance): We are not electing a pastor-in-chief. We're electing a commander-in-chief.

STEVE STRANG (Christian Publisher): My faith influences the friends that I have, the woman that I married. It affects my decision for a career, so why wouldn't it affect how I vote?

LAWTON: Religion has long had an uneasy relationship with U.S. politics. According to a recent Pew Forum survey, nearly 70 percent of Americans agree that it is important for a president to have strong religious beliefs, and more than 60 percent say they'd be less likely to support a president who doesn't believe in God. But at the same time, more than four-in-10 Americans say they get uncomfortable when politicians talk about how religious they are.

Candidates from both parties are trying to find the right balance -- a dramatic change from recent presidential elections when many people of faith felt largely ignored by the Democrats. This time around, Hillary Clinton and Barack Obama in particular have active strategies for religious outreach.

Obama's campaign held a series of faith forums in early primary states, often under the radar because the candidate himself didn't usually attend. The campaign stays in close Internet contact with its religious supporters.

Obama and Clinton have been attending churches on the campaign trail every week. On this Sunday before the South Carolina primary, Clinton visited a predominantly black mainline Presbyterian church.

Senator HILLARY CLINTON (D-NY, speaking to congregation at Northminister Presbyterian Church): Good morning. "This is the day the Lord hath made, let us rejoice and be glad in it."

Reverend RICHARD DOZIER (Northminster Presbyterian Church): Her presence here today -- I think people need to know what candidates think and be able to meet and greet in person and get a feel for them.

Senator BARACK OBAMA (D-IL, in speech): We've all got a stake in each other -- that I am my brother's keeper, that I am my sister's keeper.

LAWTON: In addition to shoring up traditional Democratic support in the black church community, both Obama and Clinton have been targeting a longtime Republican constituency -- evangelical Protestants.

Sen. CLINTON (speaking at Saddleback Church): My own faith journey is approaching a half a century, and I know how far I still have to go.

LAWTON: Laura Olson teaches political science at Clemson University in South Carolina. She says if the Democrats are able to siphon off even a few "gettable" evangelicals it could make a big difference in close elections.

Prof. OLSON: Probably at the very most we're talking about 10 percent of the evangelical population in the United States. But that might amount to two to three percent of the U.S. population overall, and if you can make inroads even with a very small number of evangelical voters, you know that helps your cause if you're the Democratic candidate.

LAWTON: On the Republican side, virtually all the campaigns have a religion strategy.

JOHN MCCAIN (R-AZ, in speech): And thank you for the work you do in supporting the preservation of the family.

LAWTON: John McCain's campaign has launched an Americans of Faith for McCain Coalition, although some former staffers say religious outreach hasn't been given enough priority. Former presidential candidate Sam Brownback is co-chairing a group called Catholics for McCain. At the March for Life this week, he read a statement of support from McCain.

Senator SAM BROWNBACK (R-KS, speaking at March for Life): And he says this: "I pledge to you to be a loyal and unswerving friend to the right to life movement."

LAWTON: Mitt Romney is continuing to woo evangelical voters.

MITT ROMNEY (in speech): It is important to recognize that while differences in theology exist between the churches in America, we share a common creed of moral convictions.

LAWTON: Romney's campaign hopes his December speech about religion has helped ease concerns among voters who may have been reluctant to vote for a Mormon. Religious outreach has been especially important for Mike Huckabee, who is relying on evangelical volunteers to help his cash-strapped campaign. At this orientation meeting in Florida, many if not most of the volunteers said they were motivated by their faith.

John Stenberger chairs Huckabee's Florida faith and values coalition.

JOHN STENBERGER (Chair, Faith and Family Values Coalition): A lot of people think we live in a secular culture. It's not true. A lot of the media and government institutions may be secular, but the people of this country are fundamentally people of faith. So I think Mike Huckabee has a message that's resonating not just with people of faith, but with all people.

LAWTON: Huckabee has the endorsement of Steve Strang, the Florida-based founder of a $40 million publishing company targeting Pentecostal and charismatic Christians. Strang supported Huckabee in his publications and is raising money for the campaign.

Mr. STRANG: I can relate to him. The things that are important to me are important to him at a gut level. You know he doesn't have to have advisors tell him what to say to the evangelical community. I mean, you know, he's one of us.

LAWTON: Evangelical support propelled Huckabee to victory in the Iowa caucuses, but in subsequent primaries evangelicals have divided their votes among Huckabee, McCain and Romney. So far, Huckabee has not gotten a lot of support from non-evangelical Republicans.

Prof. OLSON: Republican activists, Republican voters who might not want to affiliate themselves with the sort of values-voters constituency within the Republican Party, you know, might be a little bit tired of seeing the very powerful impact that that faction of the Republican Party has within GOP politics.

LAWTON: At the same time, increasing numbers of social conservatives feel taken for granted by the GOP establishment.

Mr. STRANG: They cannot win without us. But we feel like they come to us six months before the election and want our vote, and then -- and I was talking to one leader, and we kind of had this little conversation. And I said, "And six days after the election they've forgotten about us," and he said "six minutes after the election," and that's exactly how we feel.

LAWTON: Further complicating the situation, growing numbers of evangelical voters, especially younger evangelicals, are stressing a wider political agenda beyond opposing abortion and gay marriage.

RUSTY PRITCHARD (Evangelical Environmental Network): They're pro-life, and they're pro-family values, but they also care about the common good. They care about issues of poverty. They care about AIDS. They care the crisis in Darfur. And one of the things they care about is environmental issues.

LAWTON: Not all people of faith are welcoming this campaign season's emphasis on religion. Reverend Welton Gaddy of the Interfaith Alliance worries about who is excluded by the God talk.

Rev. GADDY: All of us are members of a democracy that respects religion and by constitutional guarantee respects religious differences and even no religion in a person. So if you say we're going to do faith-based outreach to voters, you run the risk of using faith as a political tool.

LAWTON: Gaddy was part of a group that ran ads in New Hampshire and South Carolina urging candidates to be more cautious in their religious rhetoric.

Rev. GADDY: We are not a nation that embraces the old theocratic idea that God chooses the leader of the nation.

LAWTON: But many religious voters are determined to see their beliefs be part of the mix in the public square, and with so much activity on so many fronts, religion will likely be prominent right up to Election Day.

I'm Kim Lawton reporting.