I expect that Democrats will first go into an anger/denial mode, after which their own truth-tellers will begin to portion out the blame for their losses. Some will blame the electorate, some will have technical explanations, but I think that most will be drawn to conclude that the blame lies mostly with the President. Once this sinks in, I think Obama will find himself in the fight of his life, besieged from the left and right, and, who knows, even sabotaged from within by his own character.
I've seen very little about Obama to make me think he has any capacity for stepping back and becoming more respectful and conciliatory in his dealings with the opposition. I expect that his use of divisive tactics is going to increase and that we're in for a couple of nasty years in politics. If it gets too nasty, I think even more political leaders will see their stars falling, possibly including the President.