In an unprecedented move, the Presbyterian Church (U.S.A.)'s highest governing body voted Thursday to allow ministers to perform same-sex marriages, ABC News reports.
The PCUSA's 221st General Assembly, which is currently meeting in Detroit, also approved an amendment to its Book of Order that would change the definition of marriage from one man and one woman to "two people."
Mark Tooley, president of the Christian conservative think tank Institute on Religion and Democracy, laments the move, saying it is indicative of a severe moral decline within the church.
"By overturning natural marriage the PCUSA is only accelerating its already fast-paced demise. It will become even smaller, whiter and older," commented Tooley.
"Only declining denominations reject historic Christian standards and in nearly every case that rejection reinforces the decline. Who respects a church that only echoes the secular world?"
"Many faithful have already quit the PCUSA and many more now will. But some faithful will remain. May the Holy Spirit bless their witness and lay the groundwork for the PCUSA's return some day to the teachings of the global church," said Tooley.
This most recent move follows a 2010 vote in which the Presbyterian Church (U.S.A.) removed a clause requiring pastors to practice fidelity in marriage or chastity in singleness, creating a large split within the denomination.
The Presbyterian Church (U.S.A.), whose General Assembly starts this week in Detroit, has experienced a decline in membership following its shifting positions. The latest membership statistics show a loss of 89,296 in 2013, preceded by a loss of 102,791 in 2012.
The Presbyterian Lay Committee released a statement expressing sorrow the action of the PCUSA General Assembly.
"The Presbyterian Lay Committee mourns these actions and calls on all Presbyterians to resist and protest them ... God will not be mocked and those who substitute their own felt desires for God's unchangeable Truth will not be found guiltless before a holy God."
Thus far, of the mainline Protestant denominations, only the United Church of Christ supports gay marriage outright. The Episcopal Church has approved a prayer service for blessing same-sex unions, ABC reports. The Evangelical Lutheran Church in America has eliminated barriers for gay clergy but allows regional and local church officials to decide their own policies on ordination and blessings for same-sex couples.