Appalachia hasn't become more republican. Bush was ideal for the region, Obama's black.
Not so fast. Over the first half of the Clinton administration Clinton improved nationwide by 3 and in Louisiana and Mississippi, yet lost ground in Kentucky and Tennessee. Gore, who won *every county* of Tennessee when running for reelection in 1990, lost the state to a presidential candidate who lost the popular vote nationwide. The trend arguably predates Bush and clearly predates Obama.
1992:
Nationwide: Clinton by 6
Tennessee: Clinton by 5
Kentucky: Clinton by 3
West Virginia: Clinton by 13
Alabama: Bush by 7
Mississippi: Bush by 9
Louisiana: Clinton by 5
Arkansas: Clinton by 18
1996:
Nationwide: Clinton by 9
Tennessee: Clinton by 2
Kentucky: Clinton by 1
West Virginia: Clinton by 15
Alabama: Clinton by 7
Mississippi: Dole by 5
Louisiana: Clinton by 12
Arkansas: Clinton by 17