Dollars to China to Buy a Barrel of Oil

We are the defacto world currency. We get to print the hell out of im because there's really no penalty, cause we can tize our debt. But that's not the case for the argentinians. They have to take their pay sos and convert them to dollars. And then what happens? Imagine we have to start converting us. Dollars to chinese currency to buy a barrel of oil. All of a sudden that print thing don't look so good. Youkno, move towards e negative interest rates, where we're taking people's money away every day. What doesn't this eventually have to come to an end? How can we can do it in?