(AP) – The United Methodist Church’s top legislative assembly convenes Sunday for a high-stakes, three-day meeting likely to determine whether America’s second-largest Protestant denomination will fracture due to divisions over same-sex marriage and the ordination of gay clergy.

While other mainline Protestant denominations – such as the Episcopal and Presbyterian (U.S.A.) churches – have embraced gay-friendly practices, the Methodist church still bans them, even though acts of defiance by pro-LGBT clergy have multiplied and talk of a possible breakup of the church has intensified.

At the church’s upcoming General Conference in St. Louis, 864 invited delegates are expected to consider three plans for the church’s future. Several Methodist leaders said they expect a wave of departures from the church regardless of the decision.

“I don’t think there’s any plan where there won’t be some division, and some people will leave,” said David Watson, a dean and professor at United Theological Seminary in Dayton, Ohio, who will be attending the conference.

Formed in a merger in 1968, the United Methodist Church claims about 12.6 million members worldwide, including nearly 7 million in the United States. In size, it trails only the Southern Baptist Convention among U.S. Protestant denominations.

The church technically forbids same-sex marriage and gays serving in the ministry, but enforcement has been inconsistent. Clergy who support LGBT rights have been increasingly defiant, conducting same-sex marriages or coming out as gay or lesbian from the pulpit. In some cases, the church has filed charges against clergy who violated the bans, yet the UMC’s Judicial Council has ruled against the imposition of mandatory penalties.

At the heart of the ideological conflict is an official UMC policy, dating from 1972, asserting that “the practice of homosexuality is incompatible with Christian teaching.”

One of the three plans, endorsed by the UMC’s Council of Bishops, would remove that language from the church’s law book and leave decisions about same-sex marriage and ordination of LGBT clergy up to regional bodies.

This proposal, called the One Church Plan, would open up many options for those who support the LGBT-inclusive practices, but it would not compel individual churches or clergy to engage in those practices.

In contrast, the proposed Traditional Plan would affirm the bans on same-sex marriage and the ordination of “self-avowed practicing homosexuals.”

The plan would strengthen enforcement of those bans, and set up procedures for churches and regional bodies to leave the UMC if they could not abide by those rules.

The third option would create three branches of the church reflecting the different approaches to LGBT issues. One branch would maintain the current bans, another would expect all its clergy and regional groups to support full LGBT inclusion, and the third would neither forbid nor require the inclusive practices. This plan would take several years longer to implement than the others.

The three plans were developed over 17 months of deliberations by a Methodist committee that was formed after conflict over LGBT policies boiled over at a General Conference in 2016. In accordance with Methodists’ long tradition of democratic policy-making, delegates in St. Louis will be free to revise any of the plans, or even consider some sort of hybrid. The delegates are split evenly between lay people and clergy.

Kenneth Carter, the Florida-based president of the Council of Bishops, is among a majority of the bishops supporting the One Church Plan, hoping it would limit any exodus by creating space for differing views on the LGBT issues.

“We’re better together than we are separated and fragmented, but I do understand that the forces that would separate us are very powerful,” Carter said.

“We’ve tried to remain together as a global body,” he added. “The challenge is simply that there are some nations where homosexuality is taboo.”

Among the supporters of the Traditional Plan is Mark Tooley, who heads a conservative Christian think tank, and has long engaged in the debate over Methodist policy.

He believes a traditionalist alliance of U.S.-based and overseas delegates will be large enough to outvote centrist and liberal delegates.

Unlike other mainline Protestant churches, the UMC is a global denomination; its greatest growth recently has been overseas. About 30 percent of the delegates in St. Louis will be from Africa – a bloc with relatively conservative views on sexuality that in the past has supported the LGBT bans.

If the Traditional Plan does prevail, Tooley says some liberal segments of the church – perhaps its Western U.S. district – might withdraw to form a new denomination.

“It would be very significant,” Tooley said.

UMC leaders are acutely aware of how searing the lengthy ideological conflict has been. In December, the Council of Bishops issued a pastoral letter expressing remorse that the buildup to the St. Louis meeting has been hurtful to many LGBT people.

“Demeaning and dehumanizing comments and attacks on LGBTQ persons in conversations related to the upcoming February Conference are a great tragedy and do violence to hearts, minds, and spirits,” the letter said. “We commit ourselves to helping people who disagree with each other to have conversations that include, honor, and respect people with different convictions.”

A localized example of the church’s internal divisions has surfaced in San Francisco, home to the liberal Glide Memorial United Methodist Church, which has 12,000 members.

The UMC’s California-Nevada conference removed two of Glide’s pastors last summer, then filed a lawsuit in December seeking to assert control over the local church property. A Glide spokesman, Sam Singer, said the regional authorities were displeased with Glide’s “open door policy” – which includes a variety of social-service programs for the needy and extensive outreach to the local LGBT community.

One of Glide’s former senior pastors is Karen Oliveto, who – after eight years at Glide – was elected by the Rocky Mountain regional body in 2016 as the UMC’s first openly lesbian bishop and is now based in Colorado. The UMC’s judicial council upheld the election result, while ruling that Oliveto’s 2014 marriage to a woman violated UMC policies for its clergy.

Oliveto hopes the delegates in St. Louis vote to end the LGBT bans; she’s unsure what would ensue if the Traditional Plan prevails.

“What that means for us, I don’t know,” she said. “I’ll be praying very deeply.”