Speaking from Wisconsin, I don't think he has that great of a chance here. Yes, he did hold a september rally here in Madison that attracted about 5000 people, so I understand his optimism. The problem is, most of the really progressive democrats in Wisconsin don't really see him as that big of a liberal. Many have come out and supported Kucinich. Clark is probably the best off in wisconsin right now in terms of endorsements from the more mainstream party leaders (most notably the Lt. Gov. who is managing his campaign here) and is polling well in the more conservative areas of the state. Plus in Milwaukee, Sharpton is polling well with black voters, a significant Dem base here, and Edwards has a very active group of lawyers pushing for him. Kerry is also in fairly good shape because Wisconsin voters, with Roman Catholic being the biggest religion, tend to vote very heavily for Catholic politicians.
All in all I think the governor has quite a battle ahead. But the promary as a whole here looks to be bloody and active. I'm so happy we aren't doing it in April like in 2000.