As we've seen from the numbers on the main page, Dean's got his cadre of supporters, no doubt about it. But he has practically zilch in the "second choice" numbers, and he has very high unfavourables. Face it: the majority of Democrats don't want him as nominee, and as they pay more attention they see this (the "early adopters" were skewed more toward his crowd, but mainstream Democrats are coming around to my POV as the caucuses approach).
As the field gets winnowed, it will only be worse for him. There were quite a few people who were, a few weeks ago, thinking they were going with Dean just to back the winner. But now that they see there are other, more palatable alternatives, he's lost that vote. All he's got left is his core support, and that won't be enough.
I've been doing my part: I am on vacation up north here, and just this weekend dissuaded a bunch of people (my mom and her friends) who were planning to back Dean. They are firmly antiwar, so I didn't see much hope in selling Edwards, but by showing them the op-ed piece by Wellstone's spokesman "Dean's No Wellstone" I got them to switch to backing Kucinich instead. So that's worth a half point each. <g>
Maybe Dean can hold out for Surgeon General. ;-)