Dude! The fair tax is the best tax idea to come along in a very long time. It ought to be inacted just to remove the IRS.
Dude! Slapping an overnight 20% increase on retail prices on everything will kill the consumer economy in short order and a depression will rapidly follow.
What will happen in your neighborhood when rents go up 30% overnight, when food costs go up 20% overnight, when medical and prescription costs go up 20% overnight, when gasoline goes up 15% overnight, and your utility, cable TV, and internet service bills go up at least 15% overnight. And that's just the start.
I think the idea needs a great deal more peer-reviewed study.