Evangelical Christians are an important voting bloc in US politics - their strong support was crucial to George Bush's narrow victories in 2000 and 2004.

And this year, South Carolina, a state with a strong Evangelical community, will be a crucial test, especially for the Republican candidates.

One of them must inspire the Evangelical vote to have any hope of becoming president in November.

Among the top issues for Evangelical voters in South Carolina and all across the United States are gay rights, abortion, and what they see as a threat to America emanating from the Islamic world.

At the Cathedral of Praise in the town of Charleston in South Carolina, pastor Mike Lewis says the September 11 attacks, the war in Iraq and events in Israel and the occupied Palestinian territories have affected Evangelicals thinking.

"I think it's very real they’re determined to do exactly what they said, which is to push Israel into the sea and to take America who stands with them."

That view was echoed by several church members who agreed to talk to Al Jazeera after the service.

Stan Hall is backing Rudolph Giuliani, the former mayor of New York.

"Clearly, the United States is faced with a threat, with an existential threat, and he seems to me the most capable guy to deal with that."

About one-quarter of the US population identify themselves as evangelical Christians and they make up a third of all Republican voters.

Israel connection

Seventy-eight per cent of evangelicals voted for George Bush in 2004.

They oppose abortion and same-sex marriages and most support prayer in public schools and taxpayer funding for religious schools.

Many also call themselves Christian Zionists, believing that God has given the Jewish people the divine right to rule over historic Palestine.

They also believe that the state of Israel must exist to set the stage for the return of Jesus.

Jan Stancil, another chruch-goer, supports former Arkansas governor Mike Huckabee.

"I like Huckabee. Because, I like him because of his values and so forth. I like him because of his record, he has a wonderful record in Arkansas, and I like him because of his stand on Israel. That’s very important to me as a Christian, that stand on Israel."

Religion will play an important role in this years election, says John Green of the Pew Forum on Religion and Public Life, an expert on religion in American politics.

"We have more candidates talking about their faith, we have more interest groups talking about how religion influences their point of view, and we have more organisations out there – on the right, on the left, and in the centre – that are trying to mobilize different kinds of religious voters.

"So it's quite possible that we might, essentially, break a new record in 2008 and have a much deeper involvement of religion and politics than even four years ago."

Even among Democrats who traditionally talk less about religion, candidates Barack Obama and Hillary Clinton, are this year openly discussing their faith.

Huckabee's people

But Evangelicals are overwhelmingly Republican and many are backing Huckabee.

He's an ordained Southern Baptist minister, staunchly conservative on social issues: he would ban gay marriage and abortion. 

A skilled campaigner with a folksy sense of humor, Huckabee frequently invokes Gods' name on the campaign trail.

In a debate with other Republicans in South Carolina last week he said of Iranian boats who had reportedly threatened US warships in the Gulf:

"Be prepared, first, to put your sights on the American vessel. And then be prepared that the next thing you see will be the gates of Hell, because that is exactly what you will see after that."

But Huckabee's populist record alarms those Republicans who are more concerned with cutting taxes and supporting big business interests, than gay rights or abortion.

If he's nominated, he could split the Republican coalition of fiscal and social conservatives.

Another Republican, Mitt Romney, the former Massachusetts Governor, is angling for Evangelical votes, with conservative positions on abortion, immigration and gay rights, and 'acceptable' positions on taxes for fiscal conservatives.

But Romney's own religion could work against him.

"On paper he would look like a pretty good candidate. But there is one problem, and that is his faith: he’s a Mormon, a member of the Church of Jesus Christ of Latter-Day Saints, and many Evangelicals have a deep skepticism towards voting for a Mormon."

In American politics, private matters of faith become public concerns and what emerges from the house of worship may be the key to winning the White House.