what would happen if the dollar became essentially worthless?
It is called hyperinflation.
See Germany 1923, Hungary 1946, Zimbabwe today.
Can you imagine the Treasury issuing a 1 Trillion Dollar note? You could buy a loaf of bread with it this afternoon but you would need 5 of them to buy that same loaf this evening.
What would happen is that other currencies of value, like the peso, would take the dollar's place along with chickens, chocolate bars and cans of tuna fish. And, of course, there would be war.
Even though the government prints the money, in this country, they can only print what is ordered by the Federal Reserve Bank which is a quasi-governmental agency "separated" from the political whims that created the German/Hungarian/Zimbabwean scenarios. It is the FedBank that actually "issues" the currency into the economy not the government itself.
Still you never know. Better stock up on tuna fish.
Edited by AZPaul3, : No reason given.