This isn't the first time United Methodist Church has tried amicable divorce

The United Methodist Church, with a U.S. membership of some 6.5 million, announced a plan to split the church because of bitter divisions over same-sex marriage and the ordination of openly gay clergy. For it to become official, the 2020 General Conference of the church in Minneapolis — such conferences are held every four years — will need to approve the plan. Individual churches would then vote on which side to join, and the disaggregation would begin.

As exhausted Methodists will affirm, this split over equality and civil rights in spiritual life has been a long time coming. Many mainline Protestants trace the simmering resentment against liberalization to decisions to ordain women, starting in the 1970s. Since then, the gap between those who want to expand inclusion and those who cite "tradition" (in the Methodist plan, those who would vote to separate would create a new denomination called Traditionalist Methodist) has grown ever wider.

This kind of schism, in which a large, centrally governed denomination fragments voluntarily (and allows those departing to take church property with them), is rare. When confronting the same division in recent decades, for example, the Episcopal Church literally stood its ground. The church resisted dissenters' attempts to take church property through extensive and costly litigation — almost always successfully.

Methodists have tried this before. Last time, in 1845, the issue was slavery. That split, too, was decades in the making.

At its founding in 1785, the Methodist denomination was explicit in calling for emancipation. But thereafter the church grew quickly. So quickly that it was the largest denomination in the United States by 1840. As they evangelized in slaveholding areas, Methodists compromised. In 1800, the church shifted to calling for "gradual emancipation," in 1808 local churches were allowed to make their own rules "regarding buying and selling slaves," and in 1824, slaveholders were gently encouraged to allow slaves to attend church.

With increasing stridency, proslavery churchmen pushed for more. They secured a resolution in 1836 that the church had no "right, wish or intention to interfere" with slavery. In 1840, the conference condemned 10,000 abolitionist petitions, saying that opponents of slavery would turn slaves into victims "and immolate them through the success of their kindness."

Proslavery churchmen even demanded the introduction of civil law into church councils after a late-1830s church trial of a white congregant for seduction included the testimony of a black man. The minister who conducted the trial was censured and the conference enacted a new rule — white church members henceforth would be tried consistent with state laws that prohibited testimony from all people of African heritage. In another controversy, the law of slavery in one state was held to override local church rules against slaveholding preachers.

Finally, Northern churchmen fought back. They challenged the legitimacy of a slaveholding bishop at the 1844 General Conference. For days, debates over slavery raged on the floor of the meeting. Antislavery forces argued that the church must not elevate slaveholding clerics to such positions of power. Newspapers began to talk openly about a crisis in the church.

The cause of the fissure: James Osgood Andrew, a bishop who asserted that his slave "Kitty" refused freedom because she loved her owners so dearly. Northerners argued that a slaveholding bishop was the last straw, the most offensive of a long series of slaveholding demands. Andrew responded that he held a slave "legally but not with my own consent." This argument conveniently ignored that Andrew had a long history of slave ownership and just that year had married a woman who brought at least 14 additional enslaved people to his household. Nonetheless, Andrew was offended that his private affairs were a matter of discussion.

The debate was more than a tiff over Andrew's household. His defenders declared that they, not the antislavery faction, had been ceding ground for years to meddlesome Northerners. They claimed to have avoided making an open defense of slavery on biblical grounds, despite the fact that slavery was not condemned in either the Old or New Testament. To them, the assault on Andrew was a betrayal of the long church tradition of conciliation.

They also argued — forcefully — that slavery was a question of lay politics, establishing a civil and political status, not religious doctrine. Slavery "belongs to Caesar, not to the church," said one South Carolina delegate. An enslaved person — say, Kitty — might be both a gallant Christian and unfree as a matter of civil law. Spiritual virtue did not entitle one to physical freedom.

This sophistry infuriated antislavery churchmen. The notion that freedom could be parsed to hold that a Christian believer was not entitled to liberty of her person was anathema to them.

The New England delegation made it clear that unless action was taken against Andrew, Methodism in the Northeast would be fundamentally compromised. Tens of thousands of Northern Methodists had already left the church for its increasingly proslavery stance; many more in the Midwest followed them. As the minister James Porter put it, the church's history of retreat from its opposition to slavery made it clear that slaveholders "were grasping power in both Church and State, and must be resisted at some time, or Northern whites would have little more liberty than Southern slaves."

Finally, a vote took place. By a tally of 111 to 69, the delegates determined that Bishop Andrew should "desist from the exercise of his office."

Immediately, Southerners threatened to leave the church. The "Protest of the Minority in the Case of Bishop Andrew" invoked the tradition of conciliation and emphasized the divide between secular and religious concerns. But the Northern majority drove deeper, regretting what they called their former "indulgence" of slavery.

The whole mess was turned over to a committee that was supposed to establish a plan with "Christian kindness and the strictest equity" — to allow an amicable split. Like the 2020 proposal, the 1844 plan permitted churches to choose (by vote) whether to leave or stay and allowed for a division of assets, including the possibility of cash payments.

But the divorce was not harmonious. The two resulting denominations hated each other. Litigation produced a U.S. Supreme Court decision (written by a proslavery associate justice) that awarded substantial money to the Southern faction. Northerners seethed.

Leading statesmen — including Daniel Webster, Henry Clay and John Calhoun, the three major architects of the Compromise of 1850 that was designed to preserve the country — all spoke with fear of the Methodist split. They saw it as an ominous sign for the future of the country.

And in fact, the new denominations created close allegiances between religious and governmental institutions on both sides, forging ties between political and spiritual concerns. Sermons in the 1860s glorified bloodletting and sustained the constant slaughter of the Civil War, then the deadliest war in human history. As one scholar put it, each side was convinced it that was the only "true" Methodism, and that it was fighting a holy war — to the death.

The lessons from this history are not comforting. For one thing, the plan for a cordial split did little to repair the bitter resentments of laity or clergy. Like many divorces, fights over money stood in for older and deeper disagreements that flared again at the first opportunity. Second, instead of repairing society, clergy from each side led the articulation of opposing national identities soaked in blood and spiritual sacrifice.

Such mutual reinforcement between government and religious institutions allows for greater and more dangerous division. It calls into question the assumption that religious entities and governments (or political parties) are truly distinct elements of American life, a key goal of disestablishment of religion at both state and national levels.

As the story of the first plan of separation illustrates, a schism that is shaped by divisions that are deeply political, and that have violent and extreme elements, may prove destructive and dangerous. Separation of church and state is designed to reduce such conflict. It was not up to the task in the Civil War era. Although today we face new, 21st-century cleavages and divisions, the precipitous rise of hate crimes and religious discrimination should alert us to the failure of the earlier separation to reduce tension.

Sarah Barringer Gordon is Arlin M. Adams professor of constitutional law and professor of history at the University of Pennsylvania. Her current book project is "Freedom's Holy Light: Disestablishment in America, 1776-1876." She wrote this article for the Washington Post.