In the absence of all other taxes and with a significant exemption, it would be okay. Otherwise we need to make the income tax steeply progressive so that the rich are paying a significantly higher amount of income as taxes.
The federal income tax brackets should be determined after all other federal, state, and local taxes are figured in in order to assure that they remain progressive.
Also, close any foreign loopholes. Unless a person is living more than half the year overseas, they pay full taxes here in the U.S.
Everybody who is a US citizen pays US taxes even if they live abroad. They get a foreign tax credit for the taxes they pay abroad, and they do get to exclude something like $75,000 from income as I recall. It is only certain kinds of income of corporate subsidiaries based abroad, that is not taxed in the US until repatriated.
