Demographics have, to a significant degree, controlled outcomes in the Democratic primary races to date, and the exit polls from WV indicate why Hillary is turning in a strong performance:
95 percent of the voters were white. 68 percent of the voters had no college degree. 55 percent made less than $50,000. 20 percent of white voters said race was important, and 85 percent of those went for Hillary. 50 percent of the voters thought Obama shared the views of Rev. Wright either "a lot" or "somewhat." 40 percent of the voters were older than 60.
So, if he needs to, Obama has some material to try to cast WV as a little unusual.