A regional Presbyterian church court in New York yesterday rejected a conservative faction's efforts to prohibit gay "unions" and block an openly gay candidate for ordination, a significant victory for Presbyterian churches that welcome gay members.

The decision by the Permanent Judicial Commission Synod of the Northeast makes the 3 million-member Presbyterian church the latest to plunge into increasingly open and bitter argument over homosexuality. What was once an uneasy but quiet detente between churches that accept gays and those that don't has in many denominations devolved into open conflict. The Presbyterians are now at a stalemate on the issue, with both sides vowing to win over the church or split off.

"This might mean that the other side has won a local skirmish but it sets the stage for the majority of the church to win the war," said Julius Poppinga, an attorney in the New Jersey case and a prominent conservative in the church who said he will appeal the decision to the General Assembly, the church's national body.

In 1997, a well-organized conservative wing of the Presbyterian church had passed an amendment to church law requiring all unmarried ministers and church officials to be sexually celibate, and defining marriage as a covenant between a man and a woman. The "Faith and Chastity Amendment" was intended to prohibit the quiet sanctioning of gay ministers and gay "unions" that had taken place for years in some Presbyterian churches.

But yesterday the regional church court interpreted the amendment narrowly in pro-gay rulings on two cases involving churches in New Jersey and New York. In the former case, the West Jersey Prebytery had accepted an application for ordination from Graham Van Keuren even though he described himself as an "openly gay man" who intended to "participate in an openly sexual way in any future relationship."

Another minister complained, leading to the recent trial, in which his attorney argued that Van Keuren "said openly he intended to violate the [church] constitution, and you can't do that." But the 10-member jury made up of local ministers and lay members rejected this argument, accepting instead the presbytery's contention that the new amendment did not cover candidates but only ordained ministers.

In the New York case, a Dobbs Ferry minister complained to the Presbytery of Hudson River after reading that a local church had celebrated a gay "holy union." But the presbytery approved the union, saying "these ceremonies do not constitute marriage" as defined by church law, and yesterday the court sided with the presbytery.

Conservatives in the church reacted strongly to the rulings. "It's a semantic ploy that doesn't work," said Poppinga. "Within the gay and lesbian community everyone refers to these things as marriages," he said. "They are using the sacred terms of marriage to sanction a lifestyle the church considers wrong and immoral."

Because they hinge on loopholes and technicalities, the rulings leave the Presbyterians in an unstable stalemate. The church is already moving toward a denominational split, with conservative and gay-friendly churches organized into different factions using different names and meeting at separate conventions.

Liberal church leaders were elated at yesterday's decisions, vowing to use them as springboards to overturn the Fidelity and Chastity Amendment by the national convention in 2001, said Robert Bohl, pastor of a large church in Kansas.

Meanwhile, conservative leaders vowed that if the appeals fail, they will work to pass a constitutional amendment explicitly banning "same-sex conjugal unions" at that same convention. If that fails, they will declare a "constitutional crisis," said Poppinga, a final step before splitting.

The escalating conflict is mirrored in other denominations. Last week, the United Methodists defrocked the Rev. Jimmy Creech for officiating at a "marriage" of two men. Creech had been put on trial once before, in 1997, for "marrying" a lesbian couple. But at the time a church tribunal ruled that the church's discouragement of holy unions did not have the force of church law. Afterward, conservatives elevated the ban to the church rule book, resulting in Creech's recent conviction.