Americans with low or no taxed income, (those who are retired, welfare recepients or dependent’s of taxpayers) now pay only those hidden taxes imbedded within the goods they consume. Fair tax advocates promise methods to compensate these people for the additional sales taxes they'll pay. (Such compensation is only feasable outside of the sales tax system itself). IMO the U.S. Congress will renege on that promise. They'll grant insufficient compensation.
There's no "fair" tax but a consumption tax could be a "fairer” tax. It will be so if the nation's economic benefit of transforming from income to consumption tax is great enough to sufficiently mitigate the gap between the promise and the compensation for low or no income taxpayers. It is dependent upon what the U.S. Congress delivers.