Correct me if I'm wrong, but Dean never had this flaky reputation when he was governor, did he? It seems all Dems become jackasses whenever they aspire to a national role in the Democratic Party. It even happened to Lieberman, who I think is basically a decent guy - he started sounding like an jerk when he ran for VP, then reverted to normalcy when that was over. I think that Dems are utterly corrupted when they try to appeal to the core Dem base and the demonic spinmeisters at the core of the party.
You're right, I think Dean was considered a pretty reasonable guy when he was Governor of Vermont (though it is a far-left state)..... he became intoxicated with what it took to rile up the far-left moonbats into a lather of rage in the 2003-04 primary campaigns, and he became more and more loony. Now he just panders to the far-left "activist base" of Moveon.org (yes, let's move on, right over the cliff). Lieberman could only get around 5-6% of the Democratic primary votes in 2004, bascically just those who are not total lunatics, so he too may be feeling the pressure to move left with the party. You have to figure that when Jimmy 'Peanut' Carter, Ted 'Swimmer' Kennedy, Joe 'Hair Plug' Biden, and Patrick 'Leaky' Leahy are consider the great "elder statesmen" of your party then sanity has been lost.....
I think he must have give the calls that came in to Hannity on him during the primaries. I think we never heard them because Vermont is such a small state... heck, look at Patrick Lahey.... he's as nuts as Dean.