To replace income tax, sales tax would have to be 18%. If you exclude housing, medical, and food you'd need a 30% rate.

Even if you give credits to the poor (which means we still track all income) how would you ever take a 'fair' amount of tax from the rich? The current tax on someone making $400K from a job is ~37% with federal/state/local. So you're reducing their tax burden more than half (if they spend 100% of what they make). In fact, they spend much less than they save, so if they buy $50K of stuff a year, their taxes are nearly eliminated ($8K in taxes versus $400K income). You can't provide the lower income people enough relief without adding to the debt (or raising the sales tax to something absurd, in which case low income people would need weekly credits or something).

This idea is insane.