WASHINGTON -- A volatile mix of religion and politics is engulfing the national debate over who can marry, further shrinking the chances of agreement on that divisive issue.
Just as religious views on when life begins deepened the cultural war over abortion, the perception of marriage as a creation of God, reserved for a man and a woman, is deepening the conflict over the desire of homosexuals to gain the right to marry.
On one side of that divide, the view is that marriage was made in heaven and that its core meaning cannot change without defying God's law. On the other side, the notion is that marriage is a creation of the law and must evolve, as law always does, to accommodate social changes.
These apparently irreconcilable positions are being played out in California, where voters will decide Tuesday on Proposition 22, which would mandate under state law that marriage is for only "a man and a woman."
The ballot measure is intended to insulate California from having to recognize gay marriages, should other states allow them.
But this is not just a California issue. Across the country, the institution of marriage is under scrutiny as seldom before.
In Vermont, religion and politics will provide the backdrop as the state Legislature takes up a proposal next week to create a marriage-like alternative. The measure would recognize a "civil union" of a gay or lesbian couple, with all the benefits and legal obligations of marriage.
Members of the clergy could, if they wished, perform "civil union" ceremonies.
The political aspects of the same-sex marriage issue are complicating the discussion within religious denominations on whether to bless homosexual unions. Later this month, an organization of Reform Jewish rabbis, meeting in Greensboro, N.C., will take up that question when it responds to a proposal to "affirm" homosexual unions through a religious ritual.
In the next months, Episcopalians, Presbyterians and United Methodists appear likely to confront the same question, fraught with theological complications -- and political consequences.
In politics, in law and in the religious community, "the same-sex marriage debate turns ultimately on the nature of marriage itself," says the American Center for Law and Justice, which opposes same-sex marriage.
A religious perspective on "the nature of marriage" is expressed by the National Conference of Catholic Bishops: "Marriage is a faithful, exclusive, and lifelong union between one man and one woman -- a union established by God with its own proper laws."
By contrast, a legal perspective is voiced by the Gay & Lesbian Advocates and Defenders, a Boston-based group that has been advocating the right to homosexual marriage in Vermont.
That organization says: "The debate over the freedom to marry is about the right to enter into the state-created institution of civil marriage only. Civil and religious marriage are not the same thing."
Many supporters of homosexual unions see marriage as a basic human right, open to all. Moreover, many view marriage as part of society's mainstream -- a mainstream that gays and lesbians want to enter to gain wider acceptance and cultural legitimacy, as well as the practical benefits.
The issue thus appears to come down to this: Many opponents of same-sex marriage want to make religious considerations paramount, controlling what the law will embrace.
Many supporters of such unions, meanwhile, want to separate religion and law and follow the definitions the law provides.
The history of marriage in America appears to have leaned toward marriage's legal side, said Nancy F. Cott, a Yale professor of history and American studies.
"In the United States," Cott said, "the religious content, the religious character of marriage, has always had to take second place to the fact that it's a civil institution.
"What makes marriage marriage is that it's a creature of the state. In contemplating changing marriage, that is what you have to focus on."
Over the nation's history, she said, "the status of husband and wife has been transformed" by "the shaping power of the state" -- influenced by "cultural and social change."
Cott noted, as examples, three areas where legislation or court rulings have produced major change in marriage: the status of husband and wife -- now legally equal partners, whereas before women were extensions of their husband's legal identity; options for leaving marriage -- now, much wider, contrasted with the law's former discouragement of divorce; and the opening of marriage to couples of different races, ending the long-standing prohibition on interracial unions.
The professor said, "American civil marriage has adopted the Christian image" of marriage as a monogamy of divine origin, with monogamy popularly assumed to mean heterosexual commitment: one man and one woman.