Why have monetary aggregates not been more influential in U.S. monetary policymaking, despite the strong theoretical presumption that money growth should be linked to growth in nominal aggregates and to inflation? In practice, the difficulty has been that, in the United States, deregulation, financial innovation, and other factors have led to recurrent instability in the relationships between various monetary aggregates and other nominal variables.
This would have put the Bundesbank far ahead of its time; after all, the importance of steering expectations as a monetary policy strategy was only recognised in the mid-1990s. On the contrary: until well into the 1990s, central bankers did not shy away from springing a surprise interest rate decision on the markets now and then.