Karen (and Bruce Bartlett) make a tremendously important point. High tax rates are counterproductive if your interest is economic improvement across the board. When the wealthy spend or invest their money, the result are mainly beneficial for people who are far poorer than they. On the other hand, if Uncle Sam makes off with millions from the likes of Bill Gates, it is apt to squander the money on hiring more federal bureaucrats, giving subsidies to businesses with good Washington connections and so forth.
If this truth ever gets out, it would ruin forever the envy card that leftist politicians like to play during elections.