DETROIT, MI – The Presbyterian Church (USA) voted to allow pastors to perform same-sex “marriages” and to change its official definition of marriage to the union of “two people” by a margin of more than three-to-one at its General Assembly in Detroit Thursday.

Seventy-six percent of voting delegates favored the measure to change the definition of marriage contained in the church’s constitution, the Book of Order, from a union of “a man and a woman” to “two people.” The vote count was 429-175.

“Who respects a church that only echoes the secular world?”

Another vote to allow PCUSA pastors to perform such ceremonies in states where gay “marriage” is legally recognized sailed through with a less robust 371-238 vote.

The Presbyterian Lay Committee, which staunchly supports the traditional definition of marriage, responded by saying, “You should refuse to fund the General Assembly, your synod, your presbytery and even your local church if those bodies have not explicitly and publicly repudiated these unbiblical actions.”

The 1.78 million member denomination is the second so-called mainline Protestant denomination to ratify same-sex “marriage,” following the United Church of Christ.

“By overturning natural marriage the PCUSA is only accelerating its already fast-paced demise,” Mark Tooley, president of the Institute on Religion and Democracy, said after the vote. “It will become even smaller, whiter, and older.”

The PCUSA had more than 3.1 million members in 1983 but has steadily declined in membership and influence.

“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?” Tooley asked.

Yesterday’s decision is the culmination of a decades-long battle over homosexuality in the denomination. In 1996, the PCUSA set forth as one of its “standards” for ordination that all pastors must “live either in fidelity within the covenant of marriage between a man and a woman, or chastity in singleness. Persons refusing to repent of any self-acknowledged practice which the confessions call sin shall not be ordained and/or installed as deacons, elders, or ministers of the Word and Sacrament.”

The church’s liberal membership attempted to repeal the requirement numerous times before they were finally successful in July 2010. Openly non-celibate homosexuals became eligible for ordination in the PCUSA the following year.

The church lost more than 100,000 members that year alone.

The denomination has been wracked by controversies over sexuality for decades, since it first adopted a statement saying homosexuality was incompatible with ordination in the late 1970s.

Tooley hoped a remnant of the Presbyterian faithful would be a force for change. “Many faithful have already quit the PCUSA and many more now will,” he said. “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.”