Under the new operating method, the banks had to take risks that interest rates might suddenly and drastically go against them. Also, banks had been expanding new loans beyond the growth of deposits, by borrowing short term funds at lower interest. The Fed new operating method would greatly increase the banks risks. The new operating method worked against the traditional mandate of the Fed which, as a central bank, was supposed to be responsible for maintaining orderly markets, which meant smooth changes in interest rates. The new operating method was a policy to induce short term pain to stabilize long term inflation expectations.
Every economist agrees that when money growth slows, interest rates go up.
The trouble with the use of the Fed Funds target to control money supply was that it had to be set by fiat which exposes the Fed to political pressure. The new operating method would let the monetary aggregates set the Fed Funds rate and provided political cover for the FOMC members if the Fed Fund needed to go to double digits. This was monetarism through the backdoor, not by intellectual commitment, but by political cowardice. It meets in secrecy four times a year with Fed officials. Four weeks before the Fed announced its new operating method, the minutes of the FAC showed that the Council had recommended to the Fed a review of its tradition operating method, before the President was alerted of the Fed's deliberation and final decision.