For more than 150 years, Baptists in the United States have splintered along political, theological and racial lines. But this week, some of the country’s largest Baptist groups — representing about 20 million believers — will meet to try to mend the old fractures and, some leaders say, present a more diverse and moderate image of their faith than the one offered by the conservative Southern Baptist Convention.

The three-day meeting of more than 30 groups — known as the New Baptist Covenant Celebration, which begins on Wednesday in Atlanta — is a result of efforts by former President Jimmy Carter to draw together long-divided Baptists.

The meeting’s statement of shared purpose, known as its covenant, calls for Baptists to focus on their traditional values, like “sharing the gospel of Jesus Christ,” and to work together on social issues like fighting poverty. It does not create a new denomination.

“I would like to see a demonstration that Christians who have different backgrounds and different political and theological orientations and geographical locations can come together in the spirit of unity,” Mr. Carter said, “not just for Baptists, but for Christians all over the world.”

But for other Baptists and experts on the faith, a central aim of the gathering seems to be to create a theological and political counterweight to the Southern Baptist Convention, which many of the groups that plan to attend have left.

Politically and theologically conservative, the Southern Baptist Convention, with 16 to 18 million members, is the largest denomination in the United States after the Roman Catholic Church.

“The sense is that the public image is dominated by the Southern Baptist Convention,” said the Rev. David W. Key, director of Baptist studies at the Candler School of Theology at Emory University in Atlanta. “It’s not that the New Baptist Covenant will do the same things as the Southern Baptist Convention does. But it’s about the brand name. ‘Can we create a brand?’ ”

The meeting falls only days before the Super Tuesday primaries, and some Southern Baptists who are critical of the gathering have said it could be part of an effort by Democrats to court Christian voters. They cite the participation of former President Bill Clinton and former Vice President Al Gore.

Mr. Carter, who is a Democrat, and others said the meeting date was the earliest one that could be arranged, and they point out that the roster of speakers includes Republicans like Senator Charles E. Grassley of Iowa, Senator Lindsey Graham of South Carolina and Gov. Sonny Perdue of Georgia.

Mike Huckabee, the Republican presidential candidate and a Southern Baptist minister, had said he would attend but backed out last year because he said he disagreed with comments Mr. Carter had made about President Bush. It is unclear whether any presidential candidates will address the gathering.

Among the religious organizations in attendance will be the four major black Baptist conventions, which three years ago came together to fashion their first united stand in almost a century on social and economic issues and to bury past differences.

Other groups include those that split with the Southern Baptist Convention over slavery in the 1800s and those that departed more recently because of the increasingly conservative slant of the denomination in modern times. That shift ushered in a more conservative theology that focuses on issues like abortion and gay rights. Southern Baptists also assert that only men can be church pastors and leaders of the household, which was another issue that alienated some adherents.

“The first thing to recognize is that the Southern Baptist Convention has moved very much to the right, became very fundamentalist, embraced certain American cultural values as though ordained by God and married the Religious Right,” said the Rev. Tony Campolo, an American Baptist minister and a speaker at the gathering.

Mr. Carter said Southern Baptist leaders had attended previous meetings he had organized. While some Southern Baptists and state organizations will be at the gathering, no leaders will attend.

The covenant’s association with Mr. Carter and Mr. Clinton, who are unpopular with many Southern Baptists, is also keeping many away, said Richard Land, the top public policy official of the Southern Baptist Convention.

“This is part of the continuing search for significance by those who lost in the struggle for control of the Southern Baptist Convention,” Mr. Land said.

The challenge for those at the meeting will be to take concrete action on issues identified as priorities, supporters and critics said. Mr. Carter said he hoped to call a meeting after Easter to plan the next steps.

“If this meeting is about shaking a fist at evangelicals and the Southern Baptist Convention, it will have a very short shelf life,” said Curtis W. Freeman, director of the Baptist House of Studies at Duke Divinity School, who will be attending the gathering. “Then it becomes about anger and pride. It becomes the negative motivation of trying to say what we are not. What I like about this particular meeting is there are positive steps we as Baptists can take together.”

Copyright 2008 The New York Times Company