I must stand correct. If ancient_geezer's table in post 626 is to be believe, states will have to add 10% inclusive to the 23% federal tax to get their current level of revenue. That's a 33% inclusive rate, or a 50% sales tax rate. My 35% guess was way too low. Imagine a 50% tax on every purchase! These guys can't be serious.
I'm curious where you're getting your 10% figure for states. I would expect it would be higher.
But I'd like to point out that unless the rate is higher than it needs to be for revenue neutrality, we're paying that much tax now and just don't realize it. Better to make it visible so people understand how much money governments waste. The hidden taxes have allowed the socialists to suck vast amounts of wealth from our nation and move it back into the hands of those who will support their agendas.