Great work. If there should be another close MD poll in the near future, I think I have a better explanation than the one listed on your website (Pentagon attack).
Kathleen Kennedy Townsend. You may not remember her, but she was the anointed for the governor's race in 2002. Kerry seems a lot like her in that there was really no there there, just empty platitudes.
I think CA and NJ can be explained the same way. Davis and McGreevey really remind me of Kerry's style. Both very unpopular in those states.
I have been toying with the idea that unpopular (and popular) governors are influencing the Presidential race quite a bit this time around, so that could very well be.