I believe the religious culture war has certainly lost steam over the last few decades in American politics. Religion is certainly not played up like it has been in the past, but the nation has a whole has become more secularized anyway. I believe secularization has been the main proponent in it being less common.
I think the religious culture war (headlined by the gay marriage issue) will come to an end soon. Moreover, I think that gay marriage will win out. However, I think there's still a lot of debating, protesting, and arguing to get through. I think we're at the climax of the religious culture war, and things will get worse before they get better.
The religious right movement has been conducting a war on the progressive side of American society and American politics for may years, and recently it has come together in the Republican party in the form of the Tea Party. To our credit as a nation, they do not seem to be winning, but there may be a backlash against things like gay marriage and affordable health care in a few years.
It is clear that when you look at the result of national elections and state wide elections across the U.S., fewer are swayed by religious issues. Pro-choice stances have gained greater favor, gay marriage is becoming increasingly accepted in society, and other issues surrounding religion are gaining less traction. That does not mean the fight is over. There are still a number of state assemblies passing restrictive abortion laws. There are still battles to fight gay marriage. The war being over would be a signal of a concession, the end of a fight. The culture war would not be considered "over" until every battle is won.
No, the religious culture war is not ending in American politics, because the religious culture war is worse than ever. Both sides are becoming more emboldened in politics in an effect to create an America that they want to see become reality. A great example of this is the frenzy over Phil Robertson's comments.