Actually the difference isn't that big when you consider that "taxes" (I'm using this to describe all (semi-)mandatory state money extraction from revenues, whether they're called tax, insurance, cotisation, etc) in European countries cover the majority of healthcare and retirement costs that Americans pay out of pocket. But still have to pay. So if the US had the same "tax" model as European countries do, the rate wouldn't be that off (VAT is usually higher than American sales taxes, income tax often has higher brackets, but Americans spend a lot more on healthcare and retirement).