Today, the Supreme Court of the United States of America struck down the Defense of Marriage Act, or DOMA, which has blocked federal benefits to married same-sex couples. They also let stand a lower-court ruling that overthrew California's Prop 8 (which would have banned same-sex marriage in that state).
They didn't assert a fundamental right of same-sex couples to be married, but the momentum here is unambiguous and, I think, inevitable. Given the generational divide on this issue--the broad and growing acceptance of homosexual couples and relationships among young Americans--we are seeing an accelerating move towards the normalization of same-sex relationships. The traditional categorical condemnation of same-sex romantic and sexual intimacy is steadily being cast off.
Conservative Christians are likely to see this as a tragic cultural shift away from the teachings of God, and will thus double down in their opposition, calling with renewed urgency for Christians to resist being sucked in by cultural "permissiveness." But these conservative voices, while still strong in most branches of Christianity, are confronting growing opposition from within. More and more Christians are adopting a progressive stance on the topic of homosexuality and same-sex marriage.
There has been a long tendency for conservative Christians to paint these internal critics of the traditional view as nothing but sell-outs to secular culture.