re: If America were to implement a flat income tax what would it need to be?

Same rate on what? In other words, what is income? Is rent different from a dividend? Is a long term gain different than a short term gain? Is passive income different than active income? If a manufacturer has a large capital investment, are they still allowed to take depreciation?

When flat taxers start talking about taxing gross income, or even net income in some instances, a rate of 23% is astronomical. Because no one ever wants to define how we get to taxable income, as opposed to income.

Mostly flat taxers talk about taxing income. That's pretty scary. Folks that's a tax increase except in rare instances. Because they keep saying income. Not net income. Not taxable income. Not adjusted gross income. Not modified adjusted gross income. They keep saying tax income.