For much of the 20th century, the language of faith infused politics on the left on issues ranging from civil rights to a living wage for farm workers.
In 1968, for example, labor leader Cesar Chavez ended a three-week fast with prayer and breaking of bread. His speech to 8,000 supporters, read by a minister, ended with the rallying call: "God help us to be men!"
But since the rise of the Christian right in the 1970s, the mantle of faith-toned politics has been ceded largely to Republicans.
Now a group of Democrats is eager to revive the historic role that religion has played in their party. It is launching a multiyear project Wednesday to amplify the religious roots of "progressive" policies, ranging from the economy and environment to social issues.
A key reason: Religion is now the biggest predictor of vote, after party identification.
In a presidential election that could pivot on a few swing states, the fact that Democrats are losing the vote of regular churchgoers by a 2-to-1 margin could be decisive.
"The gap between people who go to church regularly and those that don't is twice the gender gap," says Democratic pollster Celinda Lake. "It's huge."
To advocates, the new focus on church-pew politics represents an opportunity for peel off crucial voters without losing the party's more secular base. But big gains won't be easy, analysts say.
Protestant registered voters favor President Bush by a nine-point margin over presumptive Democratic challenger John Kerry - a gap that jumps to 18 points for those who say they attend church regularly, according to a Gallup poll released Tuesday. While Senator Kerry has jumped to an eight-point advantage among registered Roman Catholic voters in the same poll, it's a far cry from the 56-point lead enjoyed by John Kennedy among Catholics in 1960.
"Bush's pro-religion messages will surely help to solidify his appeal among more conservative Protestants, while trying to peel Catholic support away from Kerry," writes Jeffrey Jones, Gallup Poll managing editor.
The "church gap" worries Democratic activists, who are united as rarely before to try to take back the White House and the Congress this November.
"There is a public perception and a press perception, fueled by the religious right, that if you're a person of faith, you're a conservative," says John Podesta, CEO of the Center for American Progress, which Wednesday launches the new project on faith and progressive policy. "That is in dire need of correction, if you want progressive social change in this country."
The effort comes as the Bush campaign steps up efforts to mobilize the GOP vote in evangelical churches, where Republicans claim a big edge.
But winning back those votes is hard. At least at the top of the Democratic Party, advocates on issues such as abortion and gay rights were recruited not from the ranks of the dispossessed, but from professional classes. They cast their appeals in the language of law and individual rights, leaving faith-based appeals to opponents on right. In response, many conservative Democrats bolted the party.
It's not the first time that Democrats have tried to revive their religious roots. In 1992, President Clinton backed a constitutional amendment to return voluntary prayer to public schools - a rallying point for Reagan Republicans. New Democrats supported faith-based initiatives. "I have never believed the Constitution required our schools to be religion-free zones," said Sen. Joseph Lieberman, a contender on the presidential ticket in 2000 and 2004.
But such appeals have barely made a dent in the party's culture, which is increasingly secular and even hostile to faith-based appeals.
"There is a great deal of suspicion of making religious appeals of any sort inside the Democratic Party itself," says Jim Guth, a political scientist at Furman University in Greenville, S.C., who writes on religion and politics.
One reason is that Democrats, more than Republicans, are very diverse religiously. It makes it difficult to find common ground, he says. Liberal religious leaders often don't have the politically active base that Republicans have found in evangelical congregations. "There are plenty of leaders, but not many followers," he adds.
Also, groups like Emily's List, which supports abortion-rights candidates, have become top party fundraisers. Anti-abortion Democrats complain that they are excluded from speaking at national party conventions and even party websites.
Conservative activists predict that the latest effort by Democrats, too, will fizzle. "Within the Democratic Party, there is an increasingly aggressive secular left that has driven people of faith, especially conservative Catholics and evangelical Christians, into the Republican Party. They recognize how damaging it is, but they can't fix it given who pays the bills and who is in charge: Emily's List and aggressively secular left Democrats," says conservative activist Grover Norquist, president of Americans for Tax Reform.
But other analysts see an opening for change. "There has been a tendency to write off religious believers in the Democratic Party, because the party came to feel that its positions on abortion and gay rights and other cultural issues made it the enemy of religious people. Now, there is an understanding that that is not necessarily the case," says Alan Wolfe, director of the Boisi Center for Religion and American Public Life at Boston College.
"There wasn't sufficient recognition that if a person had qualms about abortion, it may be because they had serious religious beliefs and not because they were opposed to women's rights," he adds.
Podesta, former chief of staff for President Clinton, says that Democrats who are religious feel as if they have been silenced over the past few decades, and are "enthusiastic about regaining a sense of moral authority." New core values to be emphasized include inclusion, building community, taking care of each other and being good stewards of the earth.
"Some people think we're nuts and that relatively little good could come from bringing progressive religious voices back into the public square. I guess I would say history judges otherwise," he adds.
Such a new strategy could be especially helpful in heartland swing states like Michigan, Pennsylvania, Ohio, Wisconsin, and Minnesota, where Catholic voters make up a significant proportion of the population. It could also help Democrats in Southern states such as North Carolina, Louisiana and Arkansas, as well as Florida.
According to a survey by the Pew Research Center for People and the Press, nearly two-thirds who attend religious services at least once a week vote Republican. The flip side for Republicans: For those who say they seldom go to church, two-thirds vote Democratic.
"The political right and political left have agreed that religion equals the religious right. The right has done this because they want to own the issue, and some on the left have done this because they almost want to dismiss the issue," says Jim Wallis, editor-in-chief of Sojourners, a magazine covering faith and politics.