1) The "Fair Tax" is the Flat Tax with a corporate focus group rebranding campaign, and nothing more. They are "completely different" the same way 'the death tax' and 'the estate tax' are.
2) Robert E. Hall and Alvin Rashbushka, "Low Tax, Simple Tax, Flat Tax" (McGraw-Hill, 1983), p. 58. A taste:
"It is anobvious mathematical law that lower taxes on the successful will have to be made up by higher taxes on average people."
No...the Flat Tax is a single-bracket income tax that exempts investment income. The Fair Tax is a retail consumption tax with a monthly rebate. Those are two different things.
http://en.wikipedia.org/wiki/Hall%E2%80%93Rabushka_flat_taxhttp://en.wikipedia.org/wiki/FairTaxAlso, the Flat Tax would just be a replacement for the current income tax system. The Fair Tax would replace more or less all major taxes, other than duties and excises.