The 'optics' of Romney's financial disclosures aren't great. He is an immensely rich guy who paid a lot in taxes. The headline reads:

Romney Paid 13.9% Tax Rate on $21.6 Million in 2010 Income

Well, that will cause some umbrage - "Hey, I pay more than that." None of us are paying more than $3 million in taxes, but for those of us in the 35% rate and who've paid Social Security and Medicare on top, it's a real WTF moment. We certainly have paid more than 14% of our income, unless we are quite poor, and even those folks pay social security at that rate.  My own reactions?

How did he escape AMT?

Only $3 million? Why that's not even enough to cover a single Michelle Obama vacation!

But then I had to recall WHY the 15% was put in there. This was and is to reduce double-taxation.

Dividends come out of company earnings and are already taxed 35% at corporate level. So when he paid $3 million on $20M in earnings and most of it 15% qualified dividends, he was getting dividends on $20M in corporate earnings that were 'qualified' because they were  ALREADY TAXED. They were taxes at 35%. So getting $20 million in dividends means he got dividends that had already been taxes AT 35%* or another $7 MILLION.

SO IN REALITY $10 MILLION ON $20 MILLION IN QUALIFIED CORPORATE EARNINGS ENDED UP IN TAXES. This is being largely missed in the question of 'why is it only 15%' answer.

If you are a free market conservative, even if you are not favorably disposed to Romney, it's important to point this out. The Democrats are eager to gut this and the rest of the Bush tax reform and will go after it as unfair. It's not lower rate than regular earnings overall. We need to point out the double taxation and the fact that Romney and others who get qualified dividends are actually having those earnings taxed at an overall 50% tax rate.