The FairTax repeals the income tax and removes and defunds the IRS and requires that income tax records be destroyed and calls for the repeal of the 16th amendment.
The 16th cannot be repealed so long as we have any income-based tax system since that would remove any legal way for the government to raise revenue.
A flat tax has a number of serious disadvantage:
It retains the payroll/withholding system as at present.
It cannot help reduce export prices by border-adjustable taxes from prices.
It does not address the issue of raising more tax funds from the illegal economy - just like the present system.
I'm aware of that, it comes across as pie in the sky, I know how hard and almost impossible it is to pass an amendment to the constitution (or repeal one).
The 16th amendment leagalizes an income on taxes, if that was repealed first, and then replaced with a fair tax, fine, but I fear we would start with the fair tax, the 16th would not be repealed, and then we would wind up with both.
I would rather replace a flat tax with a fair tax, but, and this is key, I don't think we can get the fair tax in now without also winding up keeping a income tax, if they can dump the 16th, I'll be on board (despite the fact that I live in NYC).