One thing to take away from this election is that the whole nation is moving to the left because of Latino and other minorities votes, as well as increasing young people, social issues etc.. On the other side, there is still the old voters that believe in the so call "traditional values" that they hold for decades.
Republican did well actually, they would have won if this is the year 2000, because they did well with middle-older age white male voters.
Only way for Republican to not lose election in the future is to move to the left, much left, but if they do that, they will lose their traditional older white voters which on paper still constitutes majority of population.
So basically one of two things will happen
1. Democrats move more to the left, Republican move more to the right or stay where they are and nation became divided more than ever and Republican will keep loosing. This is similar to the States feel prior to the civil war, where both side got radicalized by their own ideology and no one wants to compromise.
2. Republicans and democrats should work together along with the media to turn the nation toward more left leaning sentiments overall, stop hating everyone in the media, stop hating the gays, stop hating the Mexican, Asians, Blacks etc... So that they can help to change the older white male's attitudes. This is actually what the civil right movements have done in the 60-70s, where it pretty much make everyone more politically correct on the outside, but whatever they feel on the inside is another matter, but the end goal is done.
The best outcome is for the 2nd case to occur, however this will be harder in today's environment, because as economy gets bad, people will be more radicalized and they tend to want to look for the "villain" from outside rather than within, this is where you are seeing Europe right now the far right political party are gaining popularity, and their main agenda is anti-immigrant, anti-outsider, anti people that does not look like me. Also there is the fact that older white males are the demographics that have the most closed mind people, simply due to their age and background.
However on the other hand, those problems are not so hard as to unable to overcome like slavery issues before the civil war. But if this keep going on where both side are getting increasing radicalized to their own believes, one way to keep the peace is by both side to have the same amount of power to balance each other out, which is very similar to the decades before the civil war broke out. However as soon as one side's power began to overriding the other side, and the other side see they cannot gain anymore from participation in the political process, it is very possible for them to take radical measures such as more independence from the Federal Government, and depends on how the government reacts, civil war is not out of the question down the line.