What's the matter with the "white working class"?

As I've mentioned before, a lot has been written about "white working class voters" recently.   A piece by Thomas Edsall is more informative than most, but it illustrates two common problems.  First, small cities and towns in Pennsylvania or Ohio or somewhere in the Midwest are taken as representing the "white working class."  Edsall's story, for example, starts by  discussing voting trends in Lehigh County, Pennsylvania (Allentown and Bethlehem).  But regardless of how you define class, any fair-sized town contains a mix of classes.    And different places have different political inclinations--for example, parts of Pennsylvania and Ohio have a tradition of Republican voting that goes back to before the Civil War.  So how a candidate is doing in any particular state or county or town may be an interesting question, but doesn't tell us much about how that candidate is doing among the working class.  Second, when survey data is used, class is usually defined by education or income, since few polls today ask people what kind of job they have.    Education and income are important influences on lots of things, but why call them "class" rather than, say, education and income?    Of course, income, education, and occupation are all related, so maybe you wind up with pretty much the same group of people regardless of the exact definition--in my next post, I will consider this issue.