Try it. Seriously. Ask a neighbor to explain middle-class versus wealthy federal income taxes. Ask him to help you understand "progressiveness" in rates. Request a bit of help understanding Mitt Romney's taxes being a lower rate than his secretary--stress the question of wage income versus dividends or capital gains. Isn't investment income from money that has already been taxed? Is that fair? Taxing taxed money seems excessive, doesn't it?
Does your neighbor have a clue?
What is a "fair share"? How about four times the rate of a middle-class wage-earner? If four times isn't yet fair, what would be?
Four Times Not Quite Good Enough
Few people would make the argument against progressiveness in a modern nation. Those who have been successful generally acknowledge the obligation to "pay it forward" and contribute a larger share than those still struggling. The question is regarding what is reasonable. Essential to the arrangement is acceptability of the higher rate.
The successful must see the higher rate as appropriate and not confiscatory. It if becomes a blatant redistribution program and can be viewed as unjust seizure of earned assets you are on the threshold of revolution.
The starting point for such a system is a population which is ignorant of how the progressive tax structure works. We are very firmly entrenched in such ignorance. Ask a neighbor.