"Consumption tax." Oy. Todd Tiahrt is worse than I thought.
Such taxes are inevitably regressive. Stupid, stupid idea. As is the idea that it would eliminate the federal tax bureaucracy.
As soon as you start talking seriously about rewriting the tax code, you have to start adding in deductions and credits for things like childcare, mortgage payments, health insurance, etc. For most people, the tax code is simple. Fill out the 1040-EZ and go on with your life.
The complexity comes from loopholes inserted for the benefit of a few rich companies or their owners. If you want to simplify the tax code, that's the Gordian knot.
In the end, the poor are harder hit on a practical level by taxes. More of their spending is "essential" in some meaningful sense (but not in a sense I care to define just now). By definition, the rich spend more of their income on non-essential goods and services, and that's what can be fairly taxed.
Any fair tax code will incorporate various carve-outs to get at that split between essential and non-essential. And that's where the bureaucracy comes in. It's unavoidable, and it's a good thing.
Flat taxes, consumption taxes and their ilk are simplistic solutions to serious, complex problems, and they appeal to people who don't care for complexity, even when it's really there. I'm looking at you, Steve Forbes. Also you, Rep. Tiahrt.