> And so lately I've been more and more attracted to the idea of a flat tax where everyone pays the same tax rate on income above a minimum amount
That's not a flat tax. It is a progressive tax with two brackets. People who reach the second bracket pay a variable overall percentage that rises the more they make. I have never heard anyone make a convincing argument that this is better that a progressive tax with multiple brackets.
In fact, a progressive rate with multiple brackets is what you get if you apply a two bracket "flat" tax serially. What I mean by that is suppose that for each major department or function of the government you had a separate tax specifically to fund that department or function, with a two bracket structure. You get a separate tax bill for each of these in some specified order, with the taxes on each being deductible when computing the taxes for the ones that follow.
If you take this to a limit, imagining a separate small two bracket tax for every single thing the government does that needs money, and then replace the thousands of very small brackets with a smooth marginal tax rate curve, you'd get a monotonically increasing curve.
That's not a flat tax. It is a progressive tax with two brackets. People who reach the second bracket pay a variable overall percentage that rises the more they make. I have never heard anyone make a convincing argument that this is better that a progressive tax with multiple brackets.
In fact, a progressive rate with multiple brackets is what you get if you apply a two bracket "flat" tax serially. What I mean by that is suppose that for each major department or function of the government you had a separate tax specifically to fund that department or function, with a two bracket structure. You get a separate tax bill for each of these in some specified order, with the taxes on each being deductible when computing the taxes for the ones that follow.
If you take this to a limit, imagining a separate small two bracket tax for every single thing the government does that needs money, and then replace the thousands of very small brackets with a smooth marginal tax rate curve, you'd get a monotonically increasing curve.