But another delegate, Gregory Morisse, who opposed the amendment, said, "Covenanted relationships are not under constitutional threat."

Hector Lopez, a minister from a small Latino church in Southern California, said he was not at first enthusiastic about same-sex marriage. But after officiating at about a dozen such ceremonies in Oregon and seeing the respect and commitment of the couples, he said, "I experienced a passionate conversion."

Several major religious groups permit same-sex unions, but do not give them the same status as marriage, including the Episcopal Church, with about 2.3 million members; the Evangelical Lutheran Church, with 5 million; and Reform Judaism, with 1.7 million.

"Today's word is not the last word in the U.C.C. about marriage," Mr. Thomas said. "It is a crucial and groundbreaking first word in a difficult but important churchwide discussion."

He said the church strove to have "diversity without division, unity without uniformity." His hope, he said, is that "we will not run from one another, because if we run from one another we run from Christ."

There was some evidence that the denomination could comfortably encompass dissenters, in part because the mood after the vote was more conciliatory than triumphant. The Rev. Barbara Headley, pastor at a predominantly black United Church of Christ church in Hartford, said she voted against the resolution and that many blacks were more "orthodox" in their interpretation of Scripture.

"There are those of us who live in the tension of affirming love and relationships for people who have not had enough of that, and feeling like the theological evidence for it just hasn't been presented," she said.