[cnn-photo-caption image= http://i.cdn.turner.com/cnn/2008/images/06/03/west.jpg caption=" Voters in the last two states, Montana and South Dakota, wrapped up the grueling coast-to-coast Democratic nominating marathon."]
(CNN) - Two very white, working-class Western states. But look closer: there are some very real differences between the two sets of Democratic primary voters in tonight’s final primary contests.
South Dakota’s primary was closed, only registered Democrats were allowed to weigh in. But roughly one in three primary voters in Montana are independent – and that group is heavily supporting Barack Obama.
Hillary Clinton may have had an easier time winning over the party’s base - but Obama’s campaign will be counting on his ability to go toe-to-toe with John McCain over independent voters