If Sam really wants to bleed the rich, he’s absolutely fighting the wrong fight. He couches his argument in empirical terms, while everyone knows that any given belief can be illustrated with appropriately chosen figures. Those in favor of lightening the tax load on the rich have their own figures as well. Those of us who aren’t advanced economics specialists probably lack the equipment to know which one is right (or if either is). The situation calls for a moral argument, which I provide here in the spirit of elevating the debate.
It is simply this: the rich owe a larger share of their income to the government, since the government is responsible for a larger share of their income than for the poor. In an anarchic situation, the wages paid for brute labor will closely reflect the wages paid them in a capitalist state: no one needs government or legal protections in order to dig a ditch, and so government policy reflects a small portion of their income.
Now someone who’s earning a million dollars a year is a different story. Under an anarchic system, their income would be zero. Government is entirely responsible for providing the protection for his wealth and the legal structure for someone to earn their living from capital or skilled labor (ie, a medical degree would be have less inherent value without a legal certification of quality). The conditions for someone to be wealthy can be created only with government intervention in legal systems, personal protection, and economic policy.
The increasing governmental cut of progressive taxation represents the increasing governmental responsibility for wealth as you go further up the income scale.