As Keynes wrote “Life and history are made up of short runs” which implies that the long run is just a sum of many different short terms. Monetary policy cannot be reduced to a short-term gimmick since our economies do not spontaneously return quickly to zero output gaps and full employment.
A final note I have offered this analysis in the spirit of so many of the discussions I have had with John. His framework has been enormously important to policymaking in the Federal Reserve, and it has yielded many benefits. Nevertheless, it's important to keep in mind that some significant practical limitations also are associated with the application of such rules in real time.