Decker, I can always count on you to rail against the flat tax. 
It's a much fairer system since it does not penalize income earners for being successful. There would be zero tax credits and zero deductions and more money would be pumped into the economy since people would have more disposable income to buy more useless crap they don't need.
Securing the ability to pay, i.e., to pay without sacrificing the necessities/quality of life, is one of the reasons a flat tax should fail. If you define fairness along those lines, the flat tax is not very good as either an income tax or a consumption (natl. sales) tax. Which people would have more disposable income? The rich? They already have that. The poor would end up paying more. Most flat tax plans I've seen have a rate between 19-23% (consumption flat taxes are 30+%). How is that not a crushing tax increase on the poor?
It's not a revenue neutral tax. The government would take a huge hit in tax revenue. Maybe we can cut the defense budget in half to help pay for this shortfall?
Also all lobbyists will disappear from planet earth, giving up in the face of the uncorruptable flat tax. It's goodness washes over all.
Oh there are the promises of good things and infinite growth. And always, the supply side wish fulfillment saves the day for these dubious scams.
No thanks, I'll stick with what we got.