We already do. By providing the “Petro-Dollar” and “Reserve Currency” (look them up), the USA creates demand for US currency and US debt, and then deflates that debt away through inflating the dollar – and american citizens obtain nearly everything in the world at a discount. This is how the USA ‘taxed’ the world for our protection, and that is precisely why the Europeans, Russians, Iranians, and Chinese want to both control oil, and replace the dominance of the dollar as the world reserve currency and as the world medium of petroleum exchange.

For all intents and purposes, the world runs on American Law, American Dollars, and American Trade Routes. Which is the value of a huge military: obtaining discounts on trade.

https://www.quora.com/Should-the-United-States-start-charging-other-countries-for-protection