How Big a Lever is the Fed Interest Rate?

Brian Wesbury's article in the WSJ has me wondering about the size of the lever of fed's interest rate -- which affects a number of economic elements directly (e.g., bank loan rates to consumers), and many, many more indirectly (e.g., capital available to businesses for expansion).

In terms of dynamic systems, we know that small effects in one part of a system have potentially large and sustained effects in other parts. And we frequently see that chasing down one factor in an economic system or health system (e.g., cholesterol level) can have unintended consequences -- or no apparent effect at all -- in other parts. Humbling stuff!