In my mind a flat tax is unrealistic. It is an ideal that I do not believe takes into account all the complexities of our society. A for instance off the top of my head. The flat tax would have the potential of being too much of a burden for the person on welfare legitimately trying to get off of it and potentially keeping them on it by decreasing the motivation to actually get off of it.

The other question that comes to mind is are there unbias studies that demonstrate that a flat tax could actually generate the kind of money necessary to effectively run the country. I know with Forbes proposals and some others there was some serious doubt raised about this concern. I personally have never investigated those proposals enough to be able to draw my own conclusion.