Both of the major parties are socially conservative and it's obvious.
capital punishment, the war on drugs, the Patriot Act, warrantless wiretaps, SSM, NDAA, "In God We Trust", the pledge of allegiance
If you expect people to be rational, you aren't being rational.
I wouldn't say social conservatism is dead, but I will say that it's taken it's first death blow. It'll still be around for awhile, but it will no longer be a large, domineering political stance that it once was. We'll probably see social conservatism as a competitive political idea on local levels for a long time, however. I think that America is finally beginning to move more toward the left overall, but it's going to be a slow process. I think one of two things will happen in the next election: social conservatives will make an even harder push than they did this time, which will end up hurting them in the long run, if we see more of the likes of Mourdock and Akin, or they'll redefine themselves, and give themselves a fresh breath of life, at least for a time. We'll probably also see the rise of third parties, but that's for another thread.