How did the Presbyterian Church (U.S.A.) change its policy on ordaining openly gay clergy in 2011?

In 2011, the Presbyterian Church (U.S.A.) changed its policy on the ordination of openly gay clergy by nullifying a 1997 constitutional amendment that had effectively barred sexually active individuals outside of marriage from serving as clergy, elders, or deacons.1

Following a majority vote by the church's presbyteries, the denomination removed this restriction, which enabled each individual presbytery to decide the question of ordination for itself. Later that same year, Scott Anderson became the first openly gay minister to be ordained by the denomination since the 1997 amendment was overturned.1