We know that mainline Protestants and Roman Catholics have a majority in favor of marriage equality. Those unaffiliated with religion are even more supportive -- which explains in part why there is such a conflict between gay folks and Christians. But it's interesting to see the trendlines.
Of course, the Roman Catholic hierarchy is an implacable foe, regardless of the view from the pew which is very supportive. Isn't it time for those supportive RC to stop living "don't ask don't tell" and stand up to their bishops?
From the Pew Forum: