The rich gave themselves low capital gains taxes and shifted their income to be capital gains, so the income tax rate is less and less relevant.
Just as an example, Mit Romney's publicized tax rate was around 14.1% in 2011 on income that very comfortably puts him in the top income tax bracket. He just doesn't pay income tax on it.
Another misconception. Well two in one post, actually.
1) Capital gains income is often first passed through a corporation, thus getting taxed at the insanely high US corp tax rate before getting taxed a second time at the moderately normal US cap gains rate. So US citizens are still paying more on average, even if it all doesn't show up as such on a tax return.
2) And Mitt's specifically! Let's count the misconceptions (note that I don't blame you - the media never described them and let the infamous "14.1%" figure stand because it's a good story):
a) Doesn't include state tax rate. That right there could easily tack on another 9%. Though it could also be zero if in Texas. Mitt of course lived in Mass, so it's just 4% or so.
b) No one deducted charitable contributions. As a Mormon, that was 10% of his income. So add another 1.4% to his tax rate there.
c) People counted his off-shore income, which is counted as income but not taxed until repatriated, as taxed at 0%. In fact it would be taxed at normal capital gains, which today is ~20% Federal + 4% Mass. Depending on the blend of foreign to domestic income, this could amount to a lot or just a little. Let's say his offshore income constituted 10% of overall income, for a ~1-2% higher average tax rate overall?
d) Most impactfully, no one's counting the Corp Tax rate which was paid before he took the Cap Gains. That's 39% Federal and another 8% Mass (~46% total), assuming that it's coming from Mass based corps. I'd say a solid chunk of his income is coming from this sort of income, probably in the ballpark of 70%, but let's just say it's 30% (of his income subject to this sort of double tax) to be super conservative.
Starting with base 14.1% + 4%(a) + 1.4%(b) + 1-2%(c) + (.3)(46%) = 21.5% just with very simple adjustments, and as high as 31.4% with a corp tax rate blended in a bit.
Once again, you are confusing nominal rates with effective rates, and simply assuming that corp. tax was paid at that nominal rate, which has a statistical likelihood so low as to be indistinguishable from zero.
Effectively, a quarter of corporations pay zero corporation tax. Considering that the whole purpose of these constructs is to reduce the tax burden, I'd wager a guess that the rates paid tend towards the low end of the scale.
Of course tax should be paid on income that was shifted off-shore for tax reasons, but of course the monied interests are lobbying for a "tax holiday", which they have "successfully" done in the past. "Success" in quotes because the policy failed to achieve the things that were used to peddle the ludicrous idea: http://online.wsj.com/news/articles/SB1000142405297020363310... It was highly successful in avoiding taxes, which is why they are lobbying for it again.
What do voluntary charitable contributions have to do with taxes (apart from him not deducting some of them in order to not have his tax rate look even more ridiculously low than it already is)?
Just as an example, Mit Romney's publicized tax rate was around 14.1% in 2011 on income that very comfortably puts him in the top income tax bracket. He just doesn't pay income tax on it.