One of the odder things about recent American politics and political journalism is that a lot of people seem to have convinced themselves that working class Americans typically vote Republican, and the Democratic base is just composed of screenwriters in the Village and their kids. Paul Krugman notes the reality:
In fact, if you look at voting behavior, low-income whites in the South are not very different from low-income whites in the rest of the country. You can see this both in Larry Bartels’s “What’s the matter with What’s the Matter With Kansas?” (pdf), Figure 3, and in a comprehensive study of red state-blue state differences by Gelman et al (pdf). It’s relatively high-income Southern whites who are very, very Republican. Can I get away with saying that rich white trash are the problem? Probably not.
What this reflects, in turn, is the odd fact that income levels seem to matter much more for voting in the South. Contrary to what you may have read, the old-fashioned notion that rich people vote Republican, while poorer people vote Democratic, is as true as ever – in fact, more true than it was a generation ago. But in rich states like New Jersey or Connecticut, the relationship is weak; even the very well off tend to be only slightly more Republican than working-class voters. In the poorer South, however, the relationship is very strong indeed.
Now what is true that things look different if you use education rather than income as your measure of class, so the idea of the upscale liberal wasn't just concocted out of thin air. And there are some compelling reasons to look at education rather than income. However, as I point out in this article on the subject, insofar as people want "working class" to mean "no college degree" that the median income for non-college whites is higher than the national median income.