Mitt Romney's comment that 47% of the electorate does not pay federal income tax is somewhat right, but it is "not that simple," noted MSNBC host Alex Wagner. While a study from the Tax Policy Center last year found that 46% of Americans did not pay individual federal income tax, many of them paid other forms of taxes, such as payroll tax.

(Steve Benan at The Maddow Blog explains how the GOP has helped to push that number to where it is today through tax cuts.)

The NOW with Alex Wagner show discussed those details Tuesday, including that it is actually 18.1% of Americans who paid zero federal income tax and zero payroll tax. The explanatory charts and video are below.

Moreover, as already pointed out, seniors make up 44% of those who do not pay federal income tax. Another 30.4% are the working poor or those who receive tax credits for their children; 5.6% are students who receive tax credits; and there are 3,000 high-income earners who also do not pay federal income tax.

Data from the Tax Foundation also showed (above) that states with the highest number of non-tax payers reside in nine southern states that tend to swing Republican (meaning in favor of Romney this year), along with Idaho.

NOW with Alex Wagner panel discussions the implications in the video below.