Why not just do a flat tax? Why is that so difficult?
Because income taxes are by natural, anti-freedom. They assume that the government has first claim over your production. Also, the definition of "income" will require that you continue to provide detailed financial information about yourself to the feds, to prove what level you should be taxed at.
From the economic side, income taxes (even flat income taxes) act like a VAT, artifically inflating the prices of goods and services, and hiding the true costs of taxes from the public.
"Why not just do a flat tax? Why is that so difficult?"
It isn't that it is difficult; it is that the flat tax doesn't address most of the economic problems that the FairTax would and history shows that it wouldn't stay flat very long. After all, it is still a flat INCOME tax.
It doesn't matter what type of tax system they come up with there are two things it won't be.
It won't be fair and it won't be less money for Uncle Sam. They may shift the burden around but you can bet it's going to be more money for them to spend.
With government growth and spending out of control there is no way that these jerks are going to reduce their glutinous intake or restrict their ability to buy votes and back door monetary support from big business and special interest groups.
Ask yourself when was the last time that the government ever spent less money than the year before?