I have thought that Dean's problem in Iowa was a few things (which I'll list in the extended section), but now I'm wondering if it really wasn't his mainstream endorsements.
Gore, Bradley, flying down south for Carter's more or less endorsement. Was this the picture of an outsider changing his tune when the clubhouse was opened? "I would never join that exclusive club... oh wait, you want me?" (I'm talking about appearance, I don't even think Dean was an outsider to begin with, but is really a life long Democrat).
Perhaps he didn't need these endorsements, and they hurt his outsider image. Disclosure: I thought they were good to take at the time... why not? It was momentum and it was counter to the people calling him a radical who was outside the party mainstream... and as I said, I didn't think he was an outsider and I -liked- seeing that proven. But now I'm thinking in the spirit of Monday morning quarterbacks and 20/20 hindsighters.
What do you think.
Other reasons:
(1) He came on too strong with the barrage of Ads and army of orange hatted out-of-staters.
(2) His Ads were too negative harping on opponents by name on issues Dean has already "won" (maybe Gep. (etc.) suckered him into this... but still)
(3) Blowing out spending limits that made him look like he WAS willing to buy an election.
(4) Constant Media attacks on trivialities
(5) Although Dean said "don't call me frontrunner before votes are cast" many many times, I saw that on C-SPAN, not CNN, and frankly, I think he (and Trippi) did endu up taking the frontrunner thing for granted in the weeks before the caucus.
PS: this isn't a post mortem for the whole primary, just an Iowa autopsy... Dean is still in it if you ask me.