But the debate can no longer be described as one between nonreligious and religious Americans. Support for same-sex marriage has risen by double digits in every major religious group since 2006. Today, solid majorities of Catholics (57 percent)—including equal proportions of white Catholics (58 percent) and Hispanic Catholics (59 percent)—and white mainline Protestants (55 percent) have joined the religiously unaffiliated (76 percent) in supporting same-sex marriage (PRRI, March 2013). The National Cathedral, which is affiliated with the mainline Episcopal Church, rang its bells at noon on Wednesday in support of the DOMA ruling and opened its doors for a special service for LGBT families and their allies “to celebrate the extension of federal marriage equality to all the same-sex couples modeling God’s love in lifelong covenants.”
....If there are literal bells ringing in support of same-sex marriage among mainline Protestants, these unheralded but significant numbers toll the fading future of religious opposition to same-sex marriage.