If the US government said that it was creating a new currency and USD were no longer the official currency, what would happen to the USD? And to be fair to the

If the US government said that it was creating a new currency and USD were no longer the official currency, what would happen to the USD? And to be fair to the USD, Bitcoins regulations are laughable simplistic compared to a "real" currency, especially since it is so heavily biased towards deflation. I do not mean to say that Bitcoin is unsound or poorly designed, just saying that the intrinsic tools available cannot compare given the scope of the initial creation.