Oklahoma voted for Clark in '04 and Edwards was expected to win there this year.
True, though of course it *didn't* vote for Edwards, but rather Hillary Clinton, who was another candidate who didn't win the nomination. But before 2004, I think it voted for every national winner in the primaries going back to 1988. In 1984 though, it voted for Hart.
Speaking of which, here's the map comparing primary winners on the Democratic side in 1984 to 2008:
green = voted for either Mondale or Jackson in 1984 and Obama in 2008
red = voted for Mondale in 1984 and Clinton in 2008
blue = voted for Hart in 1984 and Obama in 2008
gray = voted for Hart in 1984 and Clinton in 2008
LA, MS, SC, and VA are the states that voted for Jackson in '84.