"What it explains is that the party that had been the voice of working people for decades gradually lost touch with that constituency, and eventually became much more the voice of professionals. The kind of people who read the New Yorker and Slate. The Republicans weren't doing anything for working people in terms of trade, or taxes, or jobs. In fact, they were worse for them, but in some ways, culturally, the Republicans began to get closer to that group of Americans. You could say in the absence of either party doing a whole lot for them, they drifted toward the party that at least seemed to have a feel for their way of life, sounded more like them, saw the world more like them. That was a grievous illusion, but it was a powerful one in the absence of a Democratic Party that knew how to reach those voters."
Isaac Chotiner in Slate interviews George Packer about the Democratic Party and white workers.
And Thomas Frank in The Guardian uses hacked e-mail as primary sources.