The GOP is often parodied as the party of the trust fund set, but it may turn out that the wealthy are just as likely - if not more likely - to support Democrats. I suspect there could be a lot of reasons for this, but one possibility may be that there is a point at which taxes - at least at the marginal rates that are likely to be in play in the US - become irrelevant to one's lifestyle. When you make millions, the government can take quite a bit away and you still have plenty left. Since selfless champions of the poor like Ted Kennedy and Jon Corzine don't champion a wealth tax, they are unlikely to be affected much by the policies that they propose. Asking others to sacrifice, then, becomes a cheap form of sactimony.
Of course, plenty of wealthy people do try to minimize their taxes which is one of the reasons that tax revenues go up in response to tax cuts. In additon, very few people make millions and we can't fund the government by restricting high tax rates to them. The tax increases that Jon Corzine proposes may have little impact on him, but they will have a significant effect on those who have not already got theirs.