Interesting article on Slate:  Huckabee’s Tax Plan Is Brilliant, by Steven E. Landsburg:

Mike Huckabee is not my favorite candidate, though I relish the irony of an evolution-denier whose basic appeal is to voters’ most apelike instincts. But I do give him credit for one thing: an innovative tax plan that’s being trashed by journalists who almost universally fail to understand its consequences. …

Unlimited IRAs, coupled with somewhat higher tax rates, have advantages and disadvantages, but the advantages are bigger. And whatever can be said about unlimited IRAs coupled with somewhat higher tax rates can equally be said of a national sales tax.

Another alleged difference between sales and income taxes is that income taxes can be graduated, while sales taxes can’t. Maybe, maybe not. There might be a way to design a graduated sales tax. Your credit-card providers have a pretty good idea how much you spend each year, and the government could in principle use that information to set your tax rate. Yes, there are a lot of details to be worked out, and yes, it’s highly intrusive—but I’m not convinced it’s any more intrusive than what we’ve got now.

But the good news is that the details don’t matter, because there’s an easier way to design a graduated sales tax. Namely, keep the graduated income tax and add a provision for unlimited IRAs. Presto, you’ve got the equivalent of a graduated sales tax. That’s not necessarily desirable. You could well argue that a flat tax rate is a feature, not a bug.

But that’s a topic for a different column. The point of this column is that the whole flat-versus-graduated issue is quite tangential to the sales-versus-income-tax issue. And the underlying issue becomes a lot clearer once you realize that a sales tax is a modified income tax. The right question is: Is the proposed modification a good one? The answer, according to a growing consensus among macroeconomists, is: Yes.