True Cost Economics is currently creating a sizable ruckus in the academic world, and its value as a system of thought is starting to be recognized by the economic establishment. -- Brendan Themes Go there >>True Cost Economics
Combined with the fact that sales tax is tied to consumption rather than income, this leads some to the conclusion that low-income individuals and families pay a greater proportion of their incomes in sales taxes, therefore sales tax is regressive. You're supposed to read regressive as unfair.
A VAT at the federal level would be similar to state sales taxes. States would likely strongly resist any federal attempt to usurp their sales tax authority because they rely on sales tax revenue. A VAT at the federal level would likely force states to apply their sales taxes to a uniform set of goods and services.