Today's consecration of the first openly gay Episcopal bishop will be a watershed moment for American religion that will crystallize severe divisions over homosexuality among Episcopalians and their fellow Anglicans worldwide.
With the elevation of the Rev. V. Gene Robinson, the Episcopal Church will become the first major Christian denomination anywhere to choose a bishop living openly with a same-sex partner.
Reverberations from that decision will last for years, and some consequences will shake out immediately.
The split will even be evident in the venerable consecration ritual, when the congregation is asked if there is "any reason why we should not proceed." New Hampshire conservatives are expected to register formal objections.
And as the ceremony proceeds in a University of New Hampshire arena, opponents of Robinson's consecration will hold a competing Communion service at a nearby church. Others plan candlelight vigils.
The Episcopalians' most dangerous division is within their hierarchy.
About 50 bishops will attend today's ceremony and register their support for Robinson. Presiding Bishop Frank Griswold and his predecessor as head of the Episcopal Church will be among those laying hands on Robinson to make him a bishop.
But assistant Bishop David Bena of Albany, N.Y., plans to rise to read a protest from the Conference of North American Anglican Bishops, formed only Monday.
"This threatens to be the most severe break ever within the American Episcopal Church," says the Rev. Charles Henery, a church historian who opposes Robinson's elevation.
The societal implications are equally historic.
"For countless centuries, gay and lesbian people have been on the fringes of society," said Robinson, who is joining the leadership of a denomination that has long epitomized social status in America.
Robinson's consecration is especially important because churches have long been a powerful force against acceptance of same-sex behavior, says Louie Crew, a pioneering Episcopal gay activist. For many years, it was gays demonstrating outside Christian denominational meetings.
In a pointed affirmation of the gay cause, Robinson invited Crew, a second homosexual activist and his own partner _ as well as his ex-wife and their two daughters _ to join those who will ritually present him today.
In the long term, Crew predicts, thousands of homosexuals will flow into the denomination, whose membership has declined substantially and now stands at 2.3-million.
But the short-run result will be some sort of break between Americans who uphold the traditional Anglican belief that the Bible forbids gay sex, and Episcopal loyalists allied with those who believe the prohibition is obsolete or doesn't apply to modern, committed gay relationships.
The Rev. Leslie Fairfield, a conservative historian, said Robinson's consecration will create "a big mess, probably the separation of 10 to a dozen dioceses from the national church in some way" and resistance from at least 10 percent of parish clergy.
In October, the traditionalist American Anglican Council (www.americananglican.org) began forming a "Network of Confessing Dioceses and Parishes." The AAC also is collecting applications from congregations that want to be led by conservative bishops instead of their own liberal bishops.
The pleas will go to Archbishop of Canterbury Rowan Williams, the spiritual leader of the global Anglican Communion of which the Episcopal Church (www.episcopalchurch.org) is the U.S. branch.
"It's going to be very hard for us to operate together beyond this point," says Bishop Robert Duncan of Pittsburgh, an AAC leader.
He predicts that each side will blame the other, conservatives will build "a church within a church" and the national denomination will respond with "a season of litigation."
At the international level, the top leaders of Anglicanism met in October and reaffirmed the faith's opposition to same-sex activity. They also declared that most Anglicans will refuse to recognize Robinson and that many national branches will break ties with the Episcopal Church.
Fairfield, the conservative historian, thinks world Anglicanism is developing into two religions, a "postmodern" liberalism centered in churches in the West, and "the global South's biblical brand of Christianity," supported by a minority of U.S. Episcopalians.