Under the gold standard, your dollar could be exchanged for any product in the world at a floating rate, as money, but there was a kind of put embedded in the dollar: you could always put it back to the U.S. Treasury for a fixed fraction of an ounce of gold. (Similarly, a Zimbabwean dollar can be put into a U.S. dollar.) The riskier the government???s policy, the more the put is worth.