In 2005, two congregations left the Presbyterian Church (U.S.A.) In 2006, three churches departed.
But the floodgates have lifted since then as decades-old tensions between liberals and conservatives have reached breaking points.
After a 2011 decision allowing gay ordinations, 270 congregations left in 2012 and 2013. And church analysts estimate upwards of another 100 churches may leave by the end of the year as presbyteries vote on a proposal to rewrite the church's constitution to refer to marriage as being between "two people" instead of the union of "a man and a woman."
In the Evangelical Lutheran Church in America, some 600 congregations left in 2010 and 2011 following the denomination's 2009 decision allowing the ordination of pastors in same-sex relationships.
That the denominations' changing stances on gay ordinations and same-sex marriages were a key factor in the exodus is without question. But new research into why congregations decided to leave reveal differences on sexuality issues were only part of a much larger divide.
Among the broader, longstanding concerns that convinced departing congregations that they no longer had a home in their denominations that Carthage College researchers found were:
• "Bullying" tactics by denominational leaders.
• A perceived abandonment of foundational principles of Scripture and tradition.
• The devaluation of personal faith.
"The ones that left said reform was not possible," said Carthage sociologist Wayne Thompson, study leader.
The Final Conflict
Each side suffered losses in the congregational exodus, according to researchers taking an in-depth look at the process at the recent annual meeting of the Society for the Scientific Study of Religion and the Religious Research Association.
The congregations that left were larger than the typical congregation, with some having more than 1,000 members. The losses for denominations already hemorrhaging members at historic rates have been significant.
For example, the more than 70,000 members in congregations leaving the Presbyterian Church (U.S.A.) in 2012 and 2013 accounted for more than a third of the denomination' s 192,000 net membership loss for those years, researchers Joelle Kopacz, Jack Marcum and Ida Smith reported.
In turn, many of the congregations that left faced bitter battles over church properties. And a majority in the Carthage study reported at least some members left rather than switch.
So why did the congregations break away?
Leaders of churches departing from the ELCA said along with the policy on gay ordinations that the denomination was no longer a good fit for their churches and it was important for them to disassociate with the reputation of their former governing body.
More specific reasons included claims that some ELCA leaders were "dictatorial" and that the denomination was undermining the authority of scripture and was more interested in social justice work than traditional ministry, Carthage researchers John Augustine and Brian Hansen reported.
Departing Presbyterian leaders also characterized the policy on gay ordinations as "the straw that broke the camel's back," but far from the sole reason.
Their concerns included claims that the denomination was overly politicized and weakening biblical authority and traditional teaching on the divinity of Jesus.
"The situation in the PC (U.S.A.) was hopeless as I see it," said one Presbyterian pastor who left with his congregation to join the Covenant Order of Evangelical Presbyterians.
"Our new presbytery is ... trying to help us be successful without being bullied by a denomination that has turned its back on the Gospel of Jesus Christ."
It was not as if these congregations chose the most theologically conservative new homes.
The great majority of congregations leaving the Presbyterian Church (U.S.A.) chose to join the Evangelical Presbyterian Church or the Covenant Order of Evangelical Presbyterians. Few chose to join the larger Presbyterian Church in America, which does not permit women clergy.
Similarly, congregations leaving the ELCA overwhelmingly bypassed the more conservative Lutheran Church-Missouri Synod and Wisconsin Evangelical Lutheran Synod denominations for the new Lutheran Congregations in Mission for Christ and the North American Lutheran Church.
Still, the future does not look bright for reconciliation, analysts noted.
"There is an exhaustion factor of having fought for decades," Thompson said.
Among some denominational leaders, he said, there is a sense, "The bad guys have left."
And leaders of congregations departing their former mainline Protestant denominations told Carthage researchers they were happy to be in a new place.
When the church leaders were asked if they had any regrets about their decision to leave, "The only thing they'd ever say is we should have left sooner."