So could the June 3 primaries in South Dakota and Montana, which Obama is expected to win, but not by wide popular-vote margins.  ~Michael Barone

I keep seeing people treat South Dakota and Montana as if they were obviously good states for Obama, but I’ve never been clear on why.  As far as I can tell, no one has bothered to do any polling in either state, so we have no measurement of either candidate’s support.  If it’s true that “demography is destiny” and neither campaign has much luck with the other’s constituencies, what is it about the demography of South Dakota and Montana that makes these states likely to give wins to Obama?  Both states are holding primaries, not caucuses, which suggests that the results are going to look very different from the caucus tallies from neighbouring states.  Obama has tended to do well in overwhelmingly white states where they have caucuses, but not so often in primaries.  Wisconsin remains an exception that gets stranger by the day. 

Correction: There is at least one poll from about a month ago that gives Obama an advantage in South Dakota.  There seems to be no evidence for Montana one way or the other.