Quite simply, the exit polls show Hillary Clinton winning almost every demographic category possible. Groups Obama usually carried in previous primary states he lost tonight by sometimes two-to-one margins -- such as voters under the age of 40.

Voters in the West Virginia primary were overwhelmingly white (95%) and living in rural or suburban areas (97%). Clinton won 69% of white voters, including 74% of white women.

Obama has regularly carried college-educated, higher-income voters. But not in West Virginia. Clinton won 75% of those with no college education and 58% of those with a college education. She also carried every income bracket. She won liberals, moderates and conservatives all by about two-to-one.

Two outside factors also helped Clinton: 79% of Clinton voters said Bill Clinton, who carried the state in the 1992 and 1996 general elections, campaigning in the state was important; and 51% of all voters said they think Obama shares the views of his former pastor, the Rev. Jeremiah Wright -- and Clinton won 84% of them.