There's some more detail to this. There was kind of a gray area between WW2 and the end of the Bretton Woods arrangement in 1971. After 1971, the Federal Reserve Note could no longer be converted into gold by other countries' central banks.
The average citizen, after the 1930s when the gold standard was abandoned (and for a time, private gold ownership was literally outlawed and people were obligated to turn all their gold in) could not go to a bank and say "give me my $ worth of gold" but other countries could. Between the Federal Reserve Act of 1913 and that, though, one could actually redeem a Federal Reserve Note for gold.
Now the US dollar's value is assessed by comparing it to a basket of other nations' currencies and dollar foreign policy sometimes favors a cheaper dollar. An analogous situation happened with the Swiss franc when the Swiss central bank deliberately devalued it to make Swiss exports more affordable and attractive to buy again.
In 1980, the Hunt Brothers cornered the commodities market for silver by buying up billions of dollars of it and "artificially" pumping the price up over 50$/oz. This is a good example of where metallism (backing a currency with a commodity like gold or silver or both) can fail as long as the commodity itself can also be traded. It would be quite difficult to do the same to the gold market though since silver has many more industrial uses.
The currency of a nation is only as good as the government that issues it, which in a democratic form of government means constant vigilance by voting citizens over the stewards of it.
The average citizen, after the 1930s when the gold standard was abandoned (and for a time, private gold ownership was literally outlawed and people were obligated to turn all their gold in) could not go to a bank and say "give me my $ worth of gold" but other countries could. Between the Federal Reserve Act of 1913 and that, though, one could actually redeem a Federal Reserve Note for gold.
Now the US dollar's value is assessed by comparing it to a basket of other nations' currencies and dollar foreign policy sometimes favors a cheaper dollar. An analogous situation happened with the Swiss franc when the Swiss central bank deliberately devalued it to make Swiss exports more affordable and attractive to buy again.
In 1980, the Hunt Brothers cornered the commodities market for silver by buying up billions of dollars of it and "artificially" pumping the price up over 50$/oz. This is a good example of where metallism (backing a currency with a commodity like gold or silver or both) can fail as long as the commodity itself can also be traded. It would be quite difficult to do the same to the gold market though since silver has many more industrial uses.
The currency of a nation is only as good as the government that issues it, which in a democratic form of government means constant vigilance by voting citizens over the stewards of it.