Well, Bill Gates and Warren Buffet say that the extremely wealthy in the USA are under taxed. They are both extremely wealthy and donate buckets of money to charity.
I think they have a good point. Kennedy rolled taxes on the wealthy down to 75%. Today many of the top earners in the USA pay less than 13% and many no taxes at all. The lower and middle classes simply do not make enough money to ever have their taxes amount to much of anything.
It's a fairly easy fix, but the extremely wealthy are fighting it every step of the way.