Ambinder examines the GOP's dilemma:
If Republicans drop their opposition to gay marriage, the chances that Democrats will continue to pick up majorities of new and young voters will diminish. Gay issues are the civil rights issue of the time. Many of these voters see the party's implacable opposition to equal treatment for gays and simply turn away. The GOP is killing itself by giving libertarian-leaning younger voters a reason to think that the party is held hostage by a loud minority.
Those voters are right.
It is hard to imagine a GOP primary where Christian conservatives don't significantly influence the vote and the platform. Until you can imagine a primary where Christian conservatives and their anxieties and fears don't dominate the process, it is hard to imagine a pro-gay, pro-immigrant candidate breaking through. (Jon Huntsman, Jr.?) The real trap is that there are plenty of Republicans who can win national elections, plenty of conservative Republicans, but that they cannot make it through the filter of the primary, which is not suited to the demography and realities of a modern society.
David Sessions rounds up social conservative reactions to the election.