The wealthiest per capita congressional districts are now represented by Democrats who have become the party of tycoons like Buffet, Branson, Gates, Soros and others. It may be the big money have found a party even more pliant than the Republicans. With the Democrats the billionaires make a show of being philanthropic and put some solar panels on the roof of their corporate headquarters. After that it is business as usual.
Ralph Nader has a good take on this:
http://www.commondreams.org/archive/2008/01/25/6641/