There is nothing you can do about politicians being elected to make laws subject to the desires of those that elected them. You FairTaxers don't get to pass some sort of super-laws that never again get to be tampered with.How soon after the FairTax was implemented would it be before some little girl dies because her parents couldn't afford the FairTax on her life saving surgery and then you would have a unanimous vote the next week to exempt life saving surgery from the FairTax. And then preemptive health care. And then...
Of course, they will find all sorts of exemptions. The actual tax on legitimate above the board non-exempt transactions will be 50% and they'll re-enact the emergency income tax on rich people earning more than $50,000 per year, say a flat 20% or so.