I don't really think this qualifies as Dem on Dem bashing, but it's some pretty hot Lefty on Lefty action.
http://news.yahoo.com/news?tmpl=stor..._michael_moore
(Nader to Moore: "Your endorsed presidential candidate in the Democratic primaries has withdrawn. It is time for you to come home, to join your buddies and resume your only genuine role which is that of defiance and resistance.")