Since the global currency (at the moment) is the US$, the question is what happens if global trade uses something else?
Where does that leave the USA?
And based on deals between South America, Iran, Russia and others, it may be a question that needs to be answered sooner than later.
The citizens of the USA may find out what the cost of living actually is around the world, instead of their subsidised existence that they have grown used to since the Fed & ww2 changed the landscape globally.
The USA 'bankcard' bill they have been living off, may be about to expire.
Time will tell