> For a lot of people the main selling point of a flat tax is its supposed simplicity. They have fantasies of spending two minutes a year doing their taxes. I s

> For a lot of people the main selling point of a flat tax is its supposed simplicity. They have fantasies of spending two minutes a year doing their taxes. I say "supposed simplicity" because many of these proposals still include numerous deductions and exclusions, and THAT is where 99.99% of the complexity of the tax system resides. Exactly, no matter how many tax brackets you have, without the miscellaneous deductions, calculating your total amount of tax to pay involves simply looking at a table of income ranges for a set of three numbers that applies to you and then doing the calculation top_marginal_tax_rate*(income - top_tax_bracket_lower_bound)+tax_on_income_in_lower_brackets. So the entire work to calculate your tax burden is one table lookup, one addition, one subtraction and one multiplication. The flat tax proposals simplify that by getting rid of the addition (by making tax_on_income_in_lower_brackets zero) and making the table lookup only contain two rows instead of many. So you have removed one arithmetic operation(or three if you are under the 0% bracket cutoff), and cut down on the number of rows you have to scan through by a single digit number. That is completely negligible to dozens of pages of reading you would have to do if you have even relatively simple deductions.