Excellent point.
Also, I don't believe in any progressive income tax. If the tax is an American's way to contribute to the nation, then those who don't contribute are less American than those who do. Those who contribute less are less American than those who contribute more.
I don't like the income tax, but if it were my only option, I'd push for one rate that probably wouldn't have to be more than 8 or 9 percent.
A flat tax is the way to go.. and NO sales tax.