10% of 50K is a way bigger deal than 10% of 500K. IMO, taxing through spending rather than earning is much more fair than a flat tax. If for no other reason than a flat tax can't tax investment income because it isn't earned until it is realized. And that is where most of the larger earners make most of their income. If you want to know why Warren Buffet is indifferent to raising the rate on his bracket is because he knows that regardless, he will not pay much more because his wealth is largely on paper.