The money that Buffet and pay 15% on has already been taxed once when they earned it. capital gains taxation is double taxation. taxing the interest on money you put in savings after earning it (and being taxed on it) is also double taxation. If you want to do something with the tax code that would actually help, withhold SS taxes on all income including capital gains. Why should Buffet and only pay SS on the first 106K of earnings? Or, nothing at all if all their income is from capital gains?