Glad to see the CBPP take this on:
Misconceptions and Realities About Who Pays Taxes, by Chuck Marr and Brian Highsmith, CBPP: Executive Summary A recent finding by Congress’ Joint Committee on Taxation that 51 percent of households owed no federal income tax in 2009  is being used to advance the argument that low- and moderate-income families do not pay sufficient taxes. Apart from the fact that most of those who make this argument also call for maintaining or increasing all of the tax cuts of recent years for people at the top of the income scale, the 51 percent figure, its significance, and its policy implications are widely misunderstood.
- The 51 percent figure is an anomaly that reflects the unique circumstances of 2009, when the recession greatly swelled the number of Americans with low incomes and when temporary tax cuts created by the 2009 Recovery Act — including the “Making Work Pay” tax credit and an exclusion from tax of the first $2,400 in unemployment benefits — were in effect. ... Both of these temporary tax measures have since expired. In a more typical year, 35 percent to 40 percent of households owe no federal income tax. In 2007, the figure was 37.9 percent. 
- The 51 percent figure covers only the federal income tax and ignores the substantial amounts of other federal taxes — especially the payroll tax — that many of these households pay. As a result, it greatly overstates the share of households that do not pay any federal taxes. Data from the Urban Institute-Brookings Tax Policy Center show only about 14 percent of households paid neither federal income tax nor payroll tax in 2009, despite the high unemployment and temporary tax cuts that marked that year.
- This percentage would be even lower if federal excise taxes on gasoline and other items were taken into account.
- Most of the people who pay neither federal income tax nor payroll taxes are low-income people who are elderly, unable to work due to a serious disability, or students, most of whom subsequently become taxpayers. (In a year like 2009, this group also includes a significant number of people who have been unemployed the entire year and cannot find work.)
- Moreover, low-income households as a whole do, in fact, pay federal taxes. Congressional Budget Office data show that the poorest fifth of households as a group paid an average of 4 percent of their incomes in federal taxes in 2007 (the latest year for which these data are available), not an insignificant amount given how modest these households’ incomes are — the poorest fifth of households had average income of $18,400 in 2007.  The next-to-the bottom fifth — those with incomes between $20,500 and $34,300 in 2007 — paid an average of 10 percent of their incomes in federal taxes.
- Even these figures understate low-income households’ total tax burden, because these households also pay substantial state and local taxes. Data from the Institute on Taxation and Economic Policy show that the poorest fifth of households paid a stunning 12.3 percent of their incomes in state and local taxes in 2010.
- When all federal, state, and local taxes are taken into account, the bottom fifth of households paid 16.3 percent of their incomes in taxes, on average, in 2010. The second-poorest fifth paid 20.7 percent.  ...
This analysis now explores these issues in more detail. ...
- The fact that most people who do not pay federal income tax in a given year do pay substantial amounts of other taxes, and also are net federal income taxpayers over time, belies the claim that households that don’t owe income tax will form bad policy judgments because they ostensibly “don’t have any skin in the game.”
- The federal tax system is progressive overall, but state and local tax systems are regressive and undo a significant share of that progressivity. There is nothing wrong with having one part of the overall tax system shield low- and moderate-income households, who pay substantial amounts of other taxes and who generally pay federal income tax as well in other years. ...