But the reality in the US is currently worse than a flat tax. Here's what is really going on if you look at just state and local taxes (taken from here):
That's right. Currently, the more you make the less you pay! And of course, given the reality of right wing craziness in the US, the rich are screaming that so much is being taken from the, the "job creators", that the country is going down the tubes. And to prove that its going down the tubes, they've instructed their bought-and-paid-for-politicians to refuse to raise the debt ceiling so that the US will default and the economy will collapse. I guess they figure when everything come crashing down there will nobody left standing to collect taxes. Perfect!
All I can say: I now understand how and why civilizations collapsed. I guess the be landowning Romans looked out and said "I'm not going to pay for an army up on the German frontier" so the barbarians came and destroyed everything. The US has Republicans looking out over the government and the economy and saying "I don't like the fact that I pay less in taxes than the poor, I should pay even less because I'm a 'job creator' and I will sabotage the country unless they give me tax cut after tax cut". And the country will default and America as we knew it will be gone. The new barbarians will be the private police forces and "security" teams that the rich will use to enforce their will on the rapidly impoverished and disorganized population around them.