With a vote on Thursday, the Presbyterian Church USA became the biggest Christian denomination in the country to allow its ministers to marry same-sex couples in states where those marriages are legal. Previously, ministers were allowed to bless same-sex unions, but not unions that were equivalent to a marriage. 

The vote was 371-238 for the resolution, a huge change from the denomination's narrow defeat of a similar measure in 2012.  The Presbyterian Church USA has just under 2 million members and more than 10,000 congregations. The church also voted to change its constitution's definition of a marriage to gender-neutral terms, although that has to be ratified by regional Presbyterian bodies, as the Pittsburgh Post-Gazette explained. 

The Presbyterian Church USA has lost about 10 percent of its membership over the past several years. Decades ago, many of the church's more conservative congregations left the larger organization for the Presbyterian Church in America. That organization condemns homosexuality as a sin, and prohibits ordination of women and openly gay members of the church. The Presbyterian Church USA voted in 2011 to allow openly-gay Presbyterians to become ordained ministers. That vote helped to grow the membership of its more conservative rival as more conservative PCUSA members defected. 

The denomination is one of several mainline Christian organizations rethinking their stances on same-sex relationships. The United Methodist Church has been fiercely debating the denomination's prohibitions on same-sex marriage over the past several months, with a group of 80 pastors saying that the denomination could very well split over the issue. Although some Methodist members and clergy have pushed for years to reform the church's policy, the debate escalated when Frank Schaefer was found guilty of violating the church's laws when he officiated the same-sex marriage of his son. Schaefer will appeal that decision in a church hearing on Friday. The church has since shied away from trying new pastors who have officiated similar unions. 

Pew Research had a good chart earlier this week detailing where many major denominations stand on same-sex marriage. It will now need a slight update: 

Source: Pew