Fiat currency is essentially the government's IOUs denominated in themselves e.g. holding a dollar note entitles you to one dollar from the government. It only

Fiat currency is essentially the government's IOUs denominated in themselves e.g. holding a dollar note entitles you to one dollar from the government. It only has value because a government can ask others to settle part of this debt or take their property otherwise. Naturally, the amount of debt a government can issue this way is limited by the value of property it can threaten. Zimbabwe, for example, cannot reach much of valuable property despite having some guns and boots. But the USA is a very different matter.