What's the matter with West Virginia?

Kevin Williamson has an article on poverty in Appalachia.  In it, he quotes the publisher of a local newspaper in Owsley County, Kentucky:  "And when you have that many people on the draw, that’s a big majority of voters."  Oddly, he doesn't mention that Romney got over 80% of the vote in Owsley County, and this whole part of the country was a Republican stronghold in 2012.  It wasn't always this way:  I show results for West Virginia because state voting data is easier to find and work with than county data.  The figure shows Democratic share of the vote in West Virginia minus the Democratic share in the whole country for presidential elections from 1916 to 2012.  A positive number on the y-axis means that the Democratic candidate did better in West Virginia than in the country as a whole.

For most of the 20th century, West Virginia leaned Democratic (the big gap in 1924 was presumably because the Democratic nominee was from West Virginia).  In 1988 it was one of only ten states to go for Michael Dukakis.  Since 1988, the relative Democratic vote has dropped in six straight elections, and the state is now strongly Republican.

The fact that the change didn't start until about 1990 suggests that it's not primarily about race, and its steadiness since then suggests that it's not primarily about the personal qualities or styles of the candidates.  So what caused it?  I'll offer a hypothesis, although I don't have time to test it:  voting participation has fallen among people with low income and education as mining and factory work has given way to unemployment or irregular employment.   So an increasing share of voters are middle-class people who disapprove of those who are on "the draw."