The National Review Online has this excellent, anonymous piece by a self-described disgruntled Democrat who attempts to explain why Zell Miller is so angry. It's great reading, because I remember my dad, a lifelong Democrat, becoming angry in 1972 and voting for Nixon. He went back (I think) the Democrats in 1976, but four years of Jimmy Carter has made him a permament Republican.
Bottom line is this: Democrats will sell out their country to win an election. Their liberal base considers selling out America a moral necessity.