The US has never defaulted on its debt — except the four times it did
Look here, if I have the gun and you don't then when I tell you I don't owe you the money that we both know I owe you, then you better sit up and listen to what I'm telling you.
Mobsters are all the same, especially the really big ones like nation states with nuclear weapons. Try weaning your country off of the US fiat currency and go to a gold standard, see what happens next.
Saddam Hussein, Muammar Gaddafi and a few others could tell but they can't because they are dead, assassinated by US forces.