Is Huckabee's Fair Tax Feasable?

Presidential candidate Mike Huckabee is proposing a "Fair Tax" that abolishes the IRS and income tax and replaces it with a national sales tax. Today at, economist Steven E. Landsburg calls Huckabee's Fair Tax plan "brilliant." Here is an excerpt.

With an income tax, you pay up front. Earn a dollar in 2008, and you'll pay 20 cents tax in 2008. (Actually, you'll pay more, of course; I'm assuming a 20 percent tax rate for the sake of illustration.) With a sales tax, that 20 cents sits in your bank account earning interest until the day you spend your earnings. Let me say that again: Your pretax earnings sit around collecting interest until the day you withdraw and spend them. Where have we heard that before? It's exactly what happens when you invest in a traditional IRA!
So, one way to mimic the effect of a sales tax is to let you deposit every dollar you earn directly into an IRA. As far as your family—or any family—is concerned, the effects are identical. A sales tax is the exact equivalent of an income tax with a provision for unlimited IRA contributions (and no withdrawal penalties). The merits and demerits of the Huckabee tax plan are identical to the merits and demerits of a vastly liberalized IRA policy.
A lot of economists, myself included, think that there's a lot to be said for unlimited IRAs. Any conceivable tax system discourages work, which is unfortunate but unavoidable. But the current system also discourages saving, which is avoidable. A liberalized IRA policy—or, equivalently, a sales tax—eliminates that problem. The downside is that when IRAs grow, there's less income to tax, so tax rates must be higher—which increases the disincentive to work. But for the past decade or so, the macroeconomics journals have been rife with papers arguing—on highly technical grounds—that the terms of that tradeoff are well worthwhile.
See the rest of the article here.