by this comment I assume you mean that he will buy US Treasuries all along the curve in order to suppress both short and long-term interest rates – how else can he stop rates from rising?
in order to buy US Treasuries the Fed is already engaging in “quantitative easing” (which is just the latest mind-fuck for printing fiat currency as fast as possible) and you are proposing that they will increase these efforts
“Only in extremis will it proceed to the next step, where these exporters feel the future value of the dollar is so unreliable that they will not accept ANY AMOUNT of future dollars in exchange for a real good today.”
so how much “quantitative easing” can the Fed perform before we reach the “extremis” state?