This month the Supreme Court will decide whether or not to make same-sex marriage legal in the United States. While the courts and lawmakers have been wrestling with the rights of gay and lesbian Americans, so too have the country’s churches. In recent decades, more than ever, Christian denominations have been debating what the Bible says about homosexuality and what it means for LGBT persons. Several mainline Christian denominations, from the Episcopal Church to the United Church of Christ, allow clergy to perform same-sex marriage ceremonies or blessings. The Evangelical Lutheran Church in America grants congregations the power to decide the issue for themselves. And earlier this year, the Presbyterian Church (U.S.A.) voted to change its definition of marriage as a commitment “between two people,” not just between a man and a woman.

Despite rapid changes in church polity and public opinion, and with gay marriage now legal in all but 13 states, the nation’s largest mainline denomination—the United Methodist Church—remains officially opposed to same-sex marriage.

“I think that the Supreme Court decision will get attention,” said the Bishop Warner H. Brown Jr., president of the United Methodist Council of Bishops. “It will give encouragement to one side of the debate or the other, but I don’t expect the debate to change.”

Official United Methodist Church (UMC) policy holds that “all persons are individuals of sacred worth,” but that “homosexuality is incompatible with Christian teaching”—dual principles that its critics find contradictory. Ordained clergy are prohibited from officiating same-sex weddings, and “self-avowed practicing homosexuals” are forbidden from ordination. In 2004, around the same time Massachusetts became the first state to recognize same-sex marriage, the UMC declared support for “laws in civil society that define marriage as the union between one man and one woman.”

There is widespread debate within the denomination over these stances. In polling, a majority of American Methodists support same-sex marriage, but in 2012, the church reaffirmed its LGBT policies at its General Conference, a global gathering of the denomination’s nearly 13-million members that happens every four years. Two prominent pastors offered a proposal to replace current church policy with a statement that noted the disagreement within the denomination, but it was voted down. Pro-LGBT protesters disrupted the proceedings, singing the hymn “What Does the Lord Require of You,” after a proposal to reverse church policy failed in a 368-572 vote.

The next year, in 2013, the UMC again made national headlines when the Rev. Frank Schaefer from Pennsylvania was put on trial for officiating his gay son’s wedding. Schaefer was found guilty and lost his ministerial credentials. He was later reinstated on appeal and is now a pastor in California.

Including Schaefer’s, there have been 13 public complaints against UMC clergy in the past two years for being LGBT or for officiating same-sex weddings, according to the Reconciling Ministries Network, an unofficial organization of United Methodists working to make church policy LGBT-affirming. In the 45 years prior to Schaefer’s trial, there were only nine such complaints against clergy—about half of which occurred after 2004.

Some church watchers have predicted disagreements around homosexuality will bring the UMC to schism, much in the way it has disrupted the Anglican Communion. Some members have even suggested that a split is the church’s only option. Last May, the Good News movement, an organization that calls itself “the leading evangelical advocate” of the UMC, released a statement on behalf of more than 80 United Methodist pastors and theologians that called for a split in the denomination. The statement asserted a “need to recognize the reality that we – laity, clergy and even the Council of Bishops – are divided and will remain divided.”

The UMC boasts a diverse membership across the globe, and much of its growth is centered in more theologically conservative regions. Within the United States, it spans the political spectrum. After all, it is the church of both former President George W. Bush and former Secretary of State Hillary Clinton. “The UMC may be the mainline denomination that has encompassed the broadest spectrum of viewpoints on homosexuality,” says Heather White, a scholar of American religious history and author of the upcoming book Reforming Sodom: Protestants and the Rise of Gay Rights. “They encompass, in one denomination, some of America’s earliest and most radical activists for LGBT rights and also some of the most adamant supporters of what has been called the Christian Right.”

But what will its stance on same-sex marriage mean for its membership going forward? The UMC, like most Christian denominations, is facing membership decline. The church lost more than 380,000 members from its rolls between 2009 and 2013. Though church attendance is on the wane for many reasons, Public Religion Research Institute (PRRI) has found that this trend happens in part because of the relationship between religion and LGBT issues, especially when it comes to how millennials identify with the church. (Disclosure: I have worked with PRRI in the past.) A quarter of Americans who left the religious affiliation of their childhood did so, at least in part, because of policies against LGBT people. PRRI also found that nearly 6-in-10 Americans think “that religious groups are alienating young people by being too judgmental on gay and lesbian issues.”

“The more than twenty percentage point shift in support for same-sex marriage over the past decade is virtually unparalleled compared to other issues,” Robert P. Jones, CEO of PRRI, wrote in an email. He added, “Most notably, while only about one-third of religiously affiliated Americans supported same-sex marriage in 2003, nearly half—47 percent—do today.”

In many ways, the UMC’s struggles are a bellwether of the debates around LGBT rights taking place across the globe. As a lifelong United Methodist, I have watched this strife from the inside. But how are this denomination’s internal issues unique? And where can it go from here? While the rest of the country awaits the Supreme Court decision on same-sex marriage, United Methodists on all sides of the issue are busy preparing for the 2016 General Conference to be held in Portland, Oregon, next May.

As a United Methodist friend and I discussed the denomination’s complicated maze of politics and belief, he commented with a mix of melancholy and hope in his voice, “If the Supreme Court rules in support of same-sex marriage this year and we don’t change, I don’t know what will happen.”

THE UNITED METHODIST CHURCH traces its roots back to the 1700s and the leadership of British evangelist John Wesley. The current iteration of the denomination formed in 1968 with the merger of the Methodist Church and the Evangelical United Brethren Church. The denomination exists without an individual executive who can dictate policy changes. Its ultimate authority remains with the General Conference, its legislative body, made up of an equal number of clergy and laity from all over the world.

The denomination’s 1968 merger happened just as the gay rights movement was gaining momentum. Heather White notes that in those years, it was the church’s progressives who were outspoken about homosexuality, and some local churches hosted gay activists and officiated same-sex unions. “Conservative Methodists had little to say about homosexuality in the 1960s and early 70s,” White says. “During those years, the most active and vocal Methodists on the issue on homosexuality were actually progressives, who played a key role as advocates of the early gay rights movement.”

Human sexuality remained contentious within the church, and church policy often followed political policy shifts. In 1972, United Methodists began debating their stance on homosexuality after Glide Memorial Methodist Church in San Francisco made headlines when it held a same-sex ceremony. That same year, the UMC added the language that homosexuality is “incompatible with Christian teaching” to its social policy. In the 1980s, as the stigma around HIV/AIDS increased, the church passed prohibitions on ordaining gay clergy. In 1996, as the country wrestled with Defense of Marriage Act, the church issued a policy against same-sex marriages. That year, the General Conference also called on the U.S. military to refrain from excluding service-members “solely on the basis of sexual orientation”—three years after the implementation of Don’t Ask, Don’t Tell.

In September of 1998, the Rev. Greg Dell, a UMC pastor in Illinois, officiated a church wedding between two gay men—something that was specifically outlawed under church policy adopted only two years earlier. The following March, Dell became the first United Methodist minister in the United States to be penalized by the denomination for marrying a gay couple. The UMC held a trial, with a retired bishop presiding and 13 ministers acting as jury. Dell was found guilty of disobeying UMC order and discipline, and was suspended indefinitely. His suspension was later limited to one year upon appeal, and he was later reappointed as a minister, continuing to bless gay couples until his retirement. The pastor told the Illinois Wesleyan University Magazine in 2008. “Thirty percent of my church was gay. What was I supposed to say, ‘I’ll take your money, I’ll baptize your babies, but I can’t marry you if you love each other?’”

More clergy trials followed, and other ministers echoed the Rev. Dell, arguing that the prohibition on officiating same-sex marriage precluded them from upholding their mandate to minister to all persons. In the same year, Jimmy Creech was also found guilty for presiding over the ceremony of a North Carolina gay couple and stripped of his clergy credentials. In 2005, Beth Stroud was defrocked for “practices declared by the United Methodist Church to be incompatible with Christian teaching,” after acknowledging that she was in a committed lesbian relationship.

The punishments were often meted out in different ways. Some clergy, like the Rev. Amy DeLong in 2011 and the Rev. Gordon Hutchins in 2014, faced shorter suspensions but were not stripped of their credentials. And not all complaints led to clergy trials. In Michigan in 2014, the Rev. Ed Rowe and the Rev. Mike Tupper were able to avoid trial by agreeing to what the Church calls a “just resolution.” As a part of the resolution, they acknowledged that they violated church rules, but they were tasked with organizing an event series to help reduce “our church’s harmful rhetoric and actions toward LGBTQ persons.”

SOME UMC LEADERS are now seeking a middle-way to heal the fractured debates and avoid more clergy trials. Last year, the Rev. Adam Hamilton, who leads the denomination’s largest church in Kansas, and the Rev. Mike Slaughter, who leads a Methodist megachurch in Ohio, put forth what they entitled “A Way Forward for a United Methodist Church.” Citing a UMC study that found that more than 90 percent of United Methodists did not think the church should split over the human sexuality debates, Hamilton and Slaughter proposed a plan that would “entrust to each local church the authority to determine how they will be in ministry with gay and lesbian people including whether they will, or will not, allow for homosexual marriages or unions.” The plan also proposed that each regional UMC body be given the authority to decide whether or not to ordain gay and lesbian clergy.

Although more than 2,700 UMC leaders have since signed on in support of Hamilton’s plan, it is not without its critics, on the right and the left, who believe it does not go far enough. Hamilton has stood by the proposal, writing last month in a blog post against a “one-size-fits-all policy” for either side. He argued that conservatives were underestimating the pastors who have come to see this issue differently recently, and that progressives were underestimating the number of members who were not ready to support same-sex marriage.

The church writ-large is also trying to negotiate a compromise. Hoping to avoid a repeat of the contentious 2012 meeting, the Commission on General Conference, which is charged with planning the legislative gatherings, is preparing to do things differently at its 2016 conference in Portland. In April, it held a closed-door gathering, bringing together leaders from five UMC advocacy groups that span the LGBT rights spectrum. According to the United Methodist News Service, the meeting discussed how to prevent bullying of LGBT individuals and their allies, as well as how to handle protests that have become commonplace around the issue.

The commission also laid the groundwork for an alternative process for the General Conference to consider legislation related to homosexuality. The process will allow for each delegate to have input on any proposals through a series of small groups. A team elected by the General Conference will then compile the information from the small groups and craft a proposal or proposals to be considered by the full legislative body. In May, the Connectional Table—an official UMC coordinating body—voted to submit a proposal to the 2016 General Conference that would create a “third way” for clergy, allowing them to identify as gay or preside over same-sex marriages without facing charges.

Many observers—both inside and outside of the church—note that the global nature of the church, in particular its growth in Africa, where homosexuality is often still taboo, is a major hurdle for those hoping to change church policy. For the 2016 General Conference, the proportion of delegates from outside the United States will increase. But even with the increased proportion of delegates from the global church, delegates from the United States still make up 58 percent of the legislative body—enough to change policy if they were all in agreement, which of course, they are not.

Bishop Brown wants the church can find a way forward together. “I think the sentiment among the bishops is that it is our hope that a schism can be avoided and that we stay together because we’re stronger together,” he said.

The path to remain the United Methodist Church may be a rocky one, given the pain and entrenchment on all sides of a long historical struggle over sexuality. What isn’t up for debate is that next year in Portland and in the years to come, the UMC will have to decide whether it’s stronger together—or apart.

Shannon Craig Straw is a writer based in Chicago. Follow her on Twitter @ShannonStraw.