A very clear and concise look at the ongoing Romney gaffe. The wording here is important to keep in mind since it suggests there are people who pay zero taxes. Not true as summed up in the article:
One last note: paying no income tax is not the same thing as paying no federal taxes. Many zero-liability households still ante up for payroll taxes that fund Medicare and Social Security, among other things. According to an analysis from the left-leaning Center on Budget and Policy Priorities, even the lowest quintile of US income earners pay about 9 percent of their income to Uncle Sam in payroll tax.
“When all federal, state, and local taxes are taken into account, the bottom fifth of households pays about 16 percent of their incomes in taxes, on average,” according to the CBPP.