Bingo. They're looking at Dean's dollars, his poll jump in New Hamster, etc., and they want what he's got. Also, I'm noticing that among the local leftists, the dividing line is between the real loonballs (Kucinich supporters waxing googly-eyed over the Department of Peace) and the majority, who are salivating over a Dean-Bush match. Nobody cares about Gephardt or Edwards, and those who like Kerry mainly like him for Theresa's money, not his politics or personality (or lack thereof).
The defining issue for the Dems right now is the war. The Dem activists hated the war and hate our success even more. Any Dem who doesn't bash Bush on this issue might as well give up on even the possibility of getting the VP nomination.