https://en.wikipedia.org/wiki/Wildcat_banking
US banking regulation is nearly weak enough to permit this for regular banking, but not quite. However, US banking regulation is weak enough to permit it as long as you call it "cryptocurrency" instead of "private currency".
> "Commissioner Alpheus Felch recalled that one bank's "cash reserves" consisted of boxes of nails and glass topped with silver coins."
Pithy! A box that's heavy, makes good clinking noises when you shake it, and has only the tiniest bit of money in it. And so apropos for Tether. I wonder if we'll get some similarly pithy remarks about the modern wildcat banks.