Huh, interesting. During the ZIRP period (~2016-2017), I remember suggesting somewhat tongue-in-cheek here that the rational response to negative interest rates is to borrow as much money as possible, use it to raise an army, and then go conquer the people who loaned you the money. It sounds like that is actually what the U.S. did, except with a dose of diplomacy that got them to exhaust themselves fighting each other first.

It's kind of the historical embodiment of "Owe the bank $100, and you have a problem. Owe the bankers $100T, and they have a problem."