During the panic in the fall of 2008 some interpreted the explosion of the Fed's balance sheet and the monetary base (MB)—currency plus reserves of banks at the Fed—as an appropriate monetary policy response to a shift in the demand for the monetary base. That monetary policy should try to accomodate such shifts in demand is a classic monetary principle.
Evidence offered in support of that interpretation was the sharp drop in the money multiplier (m)—the ratio of money (M) to the monetary base (m = M/MB). The claim was that the Fed offset the decline in the multiplier (m) by increasing MB, thus leaving the money supply (M = m times MB) comparatively unaffected by the drop in m.
