You must get your economic tax model from the GAO. Bush's tax cuts have increased revenue. Or do you subscribe to the static version? Congress spends money. Bush has failed to veto spending bills. HE didn't spend it, congress did. Civics 101. The debt has increased every year for the last 20. What else is new? At least Bush's tax cuts have increased the revenue side.
"It's not that taxes are too low it's that spending is too high." Ronald Reagan.
But what does all this have to do with anything. The fair tax is just another way to suck up revenue, albeit a much fairer way than to steal it before it can be invested.
I agree that supply-side works and that the Bush tax cuts caused more economic activity and thus more revenue.
By the same token of economics and dynamic scoring, a huge FairTax added to the selling price of goods (aka the FairTax) will result in a decrease in consumption, and therefore a reduction in the taxable base, and a reduction in the taxes collected.
This reduction in the taxable base will necessitate an even higher FairTax rate causing further reductions in the base until some sort of equilibrium is hit or until the rate is so high that reported economic activity effectively stops and everything is being handled via barter or black market activity.