More than 350 political liberals of many faiths gathered in Washington yesterday to begin what some pollsters say is a quixotic task: restoring the voice of the religious left in the nation's political debate.

"Progressive religious voices, which historically have fueled so much social change in this country, seem to have been washed out of the public dialogue in recent years," said John D. Podesta, a Roman Catholic who was White House chief of staff under President Bill Clinton. Podesta now heads the Center for American Progress, the Democratic think tank that organized the conference to highlight the "proud past" and "promising future" of the religious left.

Speakers celebrated the role of religious liberals in the civil rights movement, protests against the Vietnam War, the nuclear freeze campaign and sanctions against South Africa's former apartheid system. They called for a stronger, more clearly religious voice against the Bush administration's foreign policy and for environmental stewardship, universal health insurance, and efforts to fight poverty at home and abroad.

Yet even as the conference at times took on the enthusiasm of a pep rally, there were sobering reflections on why the religious left lost its prominence after the 1970s and how hard it may be to regain it. At the core of those concerns was a simple set of statistics, reinforced by numerous polls: People who say they are frequent churchgoers vote Republican by a ratio of about 2 to 1.

"All the surveys show that if you ask about either church attendance or attitudes -- how important is religion to you in your daily life? -- you get the same thing: the more religious, the more conservative," Gallup pollster Frank Newport said in an interview. "I certainly remember the days when being religious meant fighting for civil rights and social justice, and it's not that those people aren't still out there. But religious liberals are a small minority today."

Some liberals dispute that conclusion.

"Church attendance is not the only indicator of living out your faith," said the Rev. Brenda Bartella Peterson, executive director of the Clergy Leadership Network, a group devoted to "leadership change" in Washington. "The vast majority of people of faith in this country are center to left, politically. But if you only measure religious commitment by butts in the pews, that's what you get."

Conference attendees also blamed the media, saying news reports tend to play up the simple dichotomy between the secular left and the religious right rather than citing the full range of religious views.

"It really bothers me that whenever the media and others talk about people of faith, they talk only about the religious right and don't seem to realize there are people like me, who grew up Baptist and believe in God and have strong religious values, but who want different policy outcomes," said Melody Barnes, a senior fellow at the Center for American Progress and a former chief counsel to Sen. Edward M. Kennedy (D-Mass.).

But some of the Roman Catholics, Protestants, Jews and Muslims at the conference also said they have felt excluded or even disdained by the secular left. The Rev. James A. Forbes Jr., senior minister at the Riverside Church in New York City, told the audience in his keynote address that "we have got to find a way not to be embarrassed" to speak about religion with secular progressives.

And there was no lack of hand-wringing among the conferees about what the religious left has done wrong.

"Part of it is our fault. We should take back the Bible, take back the theological principles and not just cede them to the religious right," said the Rev. Susan B. Thistlethwaite, a minister in the United Church of Christ and president of the Chicago Theological Seminary. "It's not good enough to talk in vague terms about values. We can do better than that. We can make the theological arguments."

Historian Taylor Branch said that in the 1970s, the abortion issue split the progressive religious alliance that had formed in the civil rights movement. Since then, the left has done no better than the right in "moving beyond polemics," he said.

"Not many people who call themselves pro-choice actually want to celebrate abortion, and not many of those who call themselves pro-life want to put women in jail for having abortions," he said. "It's more of a show than a debate, with polarizing options that aren't real. Both sides profess that they love children, but you don't really have the two sides doing very much to cooperate to reduce the number of neglected and abandoned and unwanted children, or to care for them."

The Rev. Charles Henderson, a Presbyterian Church (USA) minister who publishes the interfaith quarterly CrossCurrents, said that from the 1950s through the 1970s, the mainline Protestant denominations took for granted that their values would infuse television and the public schools. Evangelicals, who felt shut out of establishment institutions, created their own schools and broadcast outlets. "Then you wake up one day in 1984 and the Christian right is dominant, and you wonder why," he said.