Much of the Democratic Party's focus in recent years has been directed at a different crowd. The "New Democrat" style of party, hard on social liberalism and mildly supportive on free trade, isn't really a winner to the working class. Make a quick comparison of the Democrats today to the Democrats 30 years ago. 30 years ago many working class whites voted for the Democrats because they thought the Republicans would elminate protectionist trade policies and destroy the union. But the factories have kept on closing. The industry keeps moving away. The Democrats' ability to protect the worker looks weaker than ever. Half the party is more concerned about fighting for gay marriage than for the working man. Even if they gave him ObamaCare he probably doesn't trust them on that anyway.
And so often you get quotes from the Democrats like this that reek of coastal elitism:
Awesome. Take that, bigots.
The country is a different place and the Democratic Party looks different than it did 20 years ago. While you can still find traces of the old-school Dems in the south and rust belt, the national party has moved on to focus on other issues leaving behind the old union mentality that kept working class whites in a solid Democratic block.