To me a national sales tax only makes sense if you abolish the income tax. Which is doubtful for sure.
Just like sales tax, exempt food, drugs, health care etc to make it less regressive.
It gives everyone skin in the game, and no massive bureaucracy is needed to administer it. In fact, one can be largely eliminated.
I think that's the idea - eliminate the income tax and replace it with a national consumption (sales) tax. Would exempting necessities like food/drugs/healthcare and possibly providing some relief (rebate) for people under a certain income level not even things out?