I gather that you believe that all taxes (other than income taxes, mentioned specifically in the sixteenth amendment) ought to paid by the states directly based on population ("...direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers...") and that no other form of federal tax is constitutional. I also gather that you think people who believe otherwise are "stupid". There are a few problems with your argument:
- Our existing tax code imposes a number of federal taxes/fees/whatever that would not fall under the strict definition of an income tax or a tax apportioned to the states.
- The courts, so far as I know, have never adopted anything like such a narrow definition of the taxation power as (I believe) you propose.
- The Constitution specifically permits a uniform "excise" tax, which should include exactly a national sales tax as that in Cain's plan.
You already pay federal sales tax on alcohol, gasoline, internet, telephone jewelery and furs. If it's unconstitutional, someone should speak up!