Its record:
2008: Big win
2010: Landslide defeat
2012: Solid win
2014: Big defeat
2016: Big defeat
Where do Democrats go from here now that their core coalition is unable to win more than 1/4 of the last national elections?
The Democratic Party is now in the worst state it has been since the Great Depression. That should be shocking to the entire political class.
Au contraire, the indication at this point is that Clinton in fact won the most support (i.e. the most votes). But even if that does not hold up, and Trump wins, he will only win narrowly. So it can certainly not be called a failure of the Democratic/Obama coalition as such, but rather a failure of the American electoral system to reflect the will of the people. Much as it failed in 2000, and as gerrymandered congressional districts and the like have previously failed to reflect the will of the people.