The problem being, if a Democratic party does not address the problems of various minority groups, those groups have no reason to vote for Democrats. The turn to conservatism that Bill Clinton and the New Democrats represented gives the Democratic constituency no reason to be, you know, the Democratic constituency. There is the Republicans, and the Republicans Light. And the Republicans Light is always at a disadvantage in that battle. Why vote for the lesser evil?
Bill Clinton's biggest mistake was abandoning the white working class. A Democratic party which is going to be really able to win enough elections to govern needs to appeal to the working class, as well as to all the various other groups. They've lost the 'conservatives', for the conservatives really aren't in any sense conservative any longer.
They have to build a coalition. Nothing else will win. And to build a coalition, they have to address the issues of all the pieces of the coalition.