Imagine two competing digital currencies: Bitcoin vs Andolfatto's version of FedCoin, identical except for the monetary policy part (Bitcoin is bitcoin and 1 Fedcoin = 1 USD). Which would the free market choose?
I don't see how they could be identical while maintaining the peg, unless the Fed used its financial power to buy 99.9% of the coins and continue to mine almost all of them, then sell them onto the market if the price got too high. They can raise the price if it gets too low, but they can't do anything about it being too high unless they own most of it. In which case they could save a lot of money by just doing it Ripple-style and premining almost all the coins.
Of course in that case I suspect a popular fork would arise where the Fed's balance is set to zero Or actually, people would sell their Fedcoins off for bitcoins, insofar as they wanted an asset that couldn't be inflated at whim - same as people do now from fiat to BTC. Except now Bitcoin has the Fed's endorsement as a concept so the title of this thread will be validated in spectacular fashion. It would be an awesome result for the Bitcoin price.