Study: Santorum Tax Plan Swells Deficit by $900B

All of the projections are based on the taxes households would pay in 2015, presumably the first year a new president could get a plan fully implemented.

The campaigns of both Gingrich and Romney have said their tax plans would lead to economic growth, which would increase tax revenues over the long term. Santorum's website also says his tax plan would promote economic growth.

Williams said the analysis of Santorum's plan is based largely on an outline of the tax plan on Santorum's campaign website. He said the Tax Policy Center asked the Santorum campaign to clarify the details of the tax plan but didn't receive a detailed response.

Also of interest: Older Americans depend on Social Security, Medicare.>>