By Matt Wells
BBC News, New York
The most unpredictable presidential race for a generation is well under way in the US, and so far, issues of personal faith have never been far from the headlines.
God and power are firmly linked in the US political scene
In the last election, President George W Bush, a born-again Christian, won the support of the vast majority of evangelicals, while his Democratic opponent John Kerry talked as little as possible about his own Catholicism.
But in the crowded field of candidates this time, it is the Democrats who are finding it easier to describe how their faith in Jesus informs their political beliefs and experience.
Senators Hillary Clinton and Barack Obama, and former senator John Edwards, appeared in a cable TV prime-time special.
They opened themselves up to questioning by some evangelical leaders on the issues that have traditionally wounded Democratic candidates in recent campaigns: support for abortion rights, and same-sex marriage.
Three of the Republican candidates at a recent primary debate were happy to admit that they did not believe in Darwinian evolution, due to their Biblically-founded beliefs.
So what lies behind the new Democratic candidates' confidence in professing their faith in public? Is it just a question of - in effect - playing the "God card" with a view to peeling off as many evangelicals as possible?
"One of the passions I have in doing this work for my party, and my candidate, is not to play that card," said Burns Strider, who has a key advisory role on "faith outreach", right at the heart of Hillary Clinton's campaign team.
A native of the Baptist Deep South, he acknowledged that Democrats in the centre lost touch with a base that once lent them significant support, but that using faith testimony just for the sake of it would not wash.
"There's nothing monochromatic about the evangelical community... this has got to be real, and authentic," he added.
The Obama campaign also has a full-time senior staffer working on faith outreach. All candidates are aware of the positive impact of targeting religious "values-voters" in the 2006 Congressional elections.
'Source of tension'
But in purely electoral terms, there is a danger for Democratic candidates in lunging too far towards the faithful, and away from the secular, non-religious voter.
John Green is the senior fellow in religion and American politics at the Pew Forum, in Washington DC. He said: "It's possible that too much talk of religion might drive those votes away."
On Capitol Hill, it is a sign of just how important religion is to US politics that only one member of Congress has ever admitted to being an atheist - and that admission came just a few months ago.
The BBC's Heart and Soul programme visited Democratic Congressman Pete Stark, of California, in his busy ground-floor office, to find out what reaction there had been to his declaration.
He said the vast majority of e-mails he had received were from secularists around the world, praising his courage, and most of the critical response had been from Christians who said they "felt sorry" for his inability to embrace God.
On the presidential race, he had blunt advice: "Who can say more rosaries than the next person in a certain given amount of time, hardly seems to me, to be a qualification.
"I'd like to hear much more specifics about how they plan to get us universal health care," he said.
Pledge of allegiance
In the US, where freedom to practise religion - or to have no religion at all - is enshrined in the constitution, the consequences of being an atheist are electorally dire for anybody seeking public office.
Until a few years ago, the Colorado businessman Dave Habecker had served on his local town council for 13 years.
One of his fellow councillors successfully introduced the reciting of the national pledge of allegiance - in response to the Iraq war - as a sign of support for US troops, said Mr Habecker.
Religion is part of everyday life for many Americans
Ever since the mid-1950s, the pledge has contained the phrase "Under God" and at the height of the anti-communist era, US bank notes were also changed to include the inscription: "In God We Trust".
Mr Habecker refused to stand and recite the pledge, and after being branded unpatriotic, was forced to enter a fresh election contest to remove him from office. He lost by some 300 votes.
"I don't know that anybody feels elated that I was removed from office for this reason," he told the programme.
"Deep down they know that I was removed for my religious beliefs, which is anti-American. We brag about being the freest country in the world. Why do we coerce our citizens to stand and recite a pledge of allegiance? It's a paradox."
While it may be virtually impossible to survive in office without faith in a supreme being, it remains to be seen how successful the Democratic Party's new confidence in the power of personal testimony will prove to be with a divided and volatile electorate.
* You can hear Matt Wells' two-part documentary series on religion and politics in the US, on the BBC World Service's Heart and Soul programme, which airs on 21 and 28 July 21. Check your local World Service schedule for transmission times.