The GOP has lost this battle, and must now turn it into a "religious freedom" issue. They need to present to the public the notion that religion has separation from the State and that they need not be dictated to on core issues (which marriage clearly is).
It'll set up a battle royale among the advocates who will demand churches follow Federal and State laws. Religion already lost this battle when the Mormons were denied Polygamy but they're only 1% of the public. Not the nearly 1/2 who are Christians and who oppose gay marriage on religious grounds.