Repeal of the 16th ammendment is not needed for either the federal or the state government to establish a sales tax. The 16th ammendment allows the federal government to collect income tax. Repeal of that ammendment would ensure that the government would never impose BOTH the sales and income taxes.
"The 16th ammendment allows the federal government to collect income tax. Repeal of that ammendment would ensure that the government would never impose BOTH the sales and income taxes."
Not totally true. Certain types of income taxes were legal before the 16th was ratified. As KevKrom pointed out, the 16th simply expanded the types of income which could be taxed. The solution is not just to repeal the 16th, but to do what is called an "aggressive repeal" which would make ALL types of income taxes illegal. That would provide far more protection than we have today against having both.
That is exactly what FairTaxers will start to work on once the FairTax is enacted. Trying to repeal the 16th before a consensus is reached as to what proposal will replace the income tax is politically DOA.