This has been a question that has been batted around after Tuesday's results, and I think it's a pretty interesting one. First off, we should point out that there are no permanent majorities and anytime a victory leads to talk of wins for a GENERATION that's the first sign that it will never happen. On the other hand, this election, even more so than 2006, 2008 and 2010 has shown some of the real fractures and long term weaknesses in the republican coalition.
So what happens?
Well, first, let's quickly look at what needs to happen long term: The GOP needs to purge the racists from their midst, and move away from anti-gay, anti-women, anti-latino and anti-science/math positions. Why? Because if they don' t they will cease as a viable political party as demographics change.
What will actually happen?
Well, none of the things above, at least any time soon. The biggest misconception out there right now is all the important Republicans will go back to DC, agree they went a bit to far, change all their positions to something more respectable and all will be fine again. This won't happen for several reasons:
1) Changing the fundamental makeup of a political coalition isn't like flipping a switch, it's like turning around a tanker. So for starters, it's not possible for any of these changes to take place immediately even if people actually wanted to make them!
2) In order for change to occur, your coalition needs to be somewhat open to that change. If you've dedicated your life to anti gay or anti-immigrant work, you didn't wake up on Wednesday and realize you've had it wrong this whole time. This is how the Republican base feels. When Obama came out in favor of gay marriage, there was no backlash because the vast majority of Democrats already supported gay marriage. When John McCain cosposored immigration reform, the bill was killed because of anger from conservatives freaking out house republicans. Conservatives don't want immigration reform any more than they did 6 years ago. These are not beliefs that will magically going to go away overnight.
3) And that is the major problem here: These racists, anti-immigrant, anti-science, anti-women people are the republican base. And Republicans need them to get reelected. You need constituencies to stay in power in politics, and while the rest of the country is moving in a more progressive direction in all these ways, the republican base shows no signs of doing so. I firmly believe that plenty of the republicans elected to DC don't even believe half the vile BS they're spewing, but they need to keep those constituencies happy in order to not get primaried out of a job.
4) More than any other factor, politicians care about one thing: losing their jobs. If you're a Republican right now, the biggest fear of losing your jobs doesn't come from people pointing out that you're a racist, it comes from the tea party wing of the party that has successfully knocked out multiple popular Republican incumbents who where cruising to reelection. For two straight cycles, tea party primary challenges have prevented the Republican party from achieving control of the senate. These people literally give no fucks. If you were in the position of moderate Republicans, wouldn't you fear them too?
If anyone doubts how deep the crazy resides in their base, please rewatch the Republican primary debates. Booing gay soldiers. Booing Rick Perry's support of the Texas dream act. Cheering "let him die". This IS the Republican party. These aren't views that will change over time, the only thing that will change over time is the people.
The Republican party will eventually evolve and break free of the bigoted neanderthals who are currently driving the ship. That change will come in 20-30 years, not because the GOP wised up and put a few more non-white faces on stage at their convention, but because in 20-30 years, most of the current Republican base will be dead.