Earlier quoted context omitted.
I misspoke: it's not that Romney pays a lower average income tax rate, but pays a lower average federal tax rate, including payroll. For most people, income taxes make up a negligible part of that total tax burden. I doubt the charitable giving would be a problem, and I'm also skeptical of the "Romney took a tax amnesty in 2009" theory. At this point I think it's mostly bull-headedness: Romney thinks no one has a rig…
For most people, income taxes make up a negligible part of that total tax burden. Ignoring the employer "contribution" sleight-of-hand, payroll taxes in 2012 are 4.2% SS + 1.45% Medicare, or 5.65%. Adding in the income tax burden, and you're still looking at a total Federal tax burden of under 12%.
Most very wealthy don't spend nearly what they earn, so the effect of sales tax is negligible.