In case there's any lingering confusion about just how ridiculous this policy is, Jon Chait sets the record straight:
Basically, trying to explain why the Fairtax is a bad idea is like trying to explain why having trained elephants perform open-heart surgery on every first-grader in America is a bad idea. The whole idea is one bit of lunacy stacked upon another, so when you focus on any one element of it, you let the other side suck you into into arguments about details -- Maybe there could be benefits to preemptively fixing the hearts of six year olds! Perhaps elephants do have the potential intelligence to one day perform this task!! -- that inadvertently make the plan sound semi-credible.
If you're still not convinced, take a look at Brad DeLong's piece in Salon this week.