We can have a progressive tax rate that is simple. Unfortunately, people such as Grover Norquist make it extremely hard. They want our current tax system to be as complicated as possible so then they can say, "Hey! Let's just do a flat tax." Thus shifting the burden of taxes from the rich to the middle class. He actually raised heavy objections when California implemented the ReadyReturn system. [1]
"With the prebate program in effect, those earning less than $15,000 per year would see their share of the federal tax burden drop from -0.7 percent to -6.3 percent. Of course, if the poorest Americans are paying less under the FairTax plan, then someone else pays more. As it turns out, according to the Treasury Department, “someone else” is everybody earning between $15,000 and $200,000 per year." [1]
[1] http://www.nbcnews.com/id/8134597/ns/business-motley_fool/t/...