The Fed is waiting in the wings to supply the liquidity backstop that the ECB cannot provide. Readers are welcome to do homework on the $16T worth of dollar swap lines the Fed activated during the first round of this crisis. I would not be surprised if those swap lines have been multiplied several times over. Hyperinflation in the U.S. and Europe has not yet occurred because all of that magic Fed juice has not leaked out into wages; it has remained locked inside commercial banks' balance sheets. I am not sanguine enough to presume that this condition will hold throughout the remainder of this crisis. Transmission mechanisms are all that is necessary; a politically popular push for home mortgage relief with direct six-figure gifts to bankrupt Americans or Europeans would start the boulder rolling downhill.
In other words, more gigantic dollar swaps increase the risk of the hyperinflationary genie being let out of the bottle. Using even more creative Fed tools - like direct loans to troubled European banks to prevent them from collapsing - raises the risk even further.