> Chomsky says that the lower 70% of the population has no effect on policy, but there is plenty of evidence to the contrary. The U.S. system of income taxation is progressive and refundable, meaning that there is substantial transfer of wealth from the richest people to the poorest.

No, it doesn't mean that, because income tax isn't the only tax (or even the only tax on incomes, as the payroll tax, which is regressive, also exists, and, on top of that, forms of income that tend to be distributed more to the richest -- long term cap gains -- have preferential tax treatment over other income), and because while the nominal rates are progressive the distribution of deductions and credits (including refundable credits) are not.