In a democratic society, I would argue that decisions regarding interest rates, both long and short term, should be made by the elected government. They used to be. However, for nearly 20 years, short term rates in the UK have been set by the BoE. The level of short term interest rates is important and it can be adjusted to stimulate a slowing economy or slow an overstimulated economy. But there are other adjustments that can be made too.
Just as a pilot has all the control levers at his disposal when he’s flying a plane (if he, or she, does hand over to the co-pilot it would be all the controls not just one) then all the controls need to be either in the hands of government or the hands of the central bank.
But just who has the controls when it comes to controversial policy decisions like QE? Does an independent Bank of England decide, all on its own, to buy up £375 billion of government securities from the private financial sector? I don’t think so!
QE is no big deal. That’s not a common view, I’ll agree, but from a scientific perspective, there seems to be no reason why the issue of government , or the BoE if you prefer, IOUs in the form of cash should be any more or less inflationary to the economic system than the issue of IOUs in the form of gilts (treasury bonds). If it is necessary to buy back gilts from the private sector to control longer term interest rates then that’s what needs to happen.
So why not give control of the fiscal deficit to the BoE too? The BoE could calculate the best combination of fiscal and monetary policy, including whatever level of QE is needed, and tell the government what it needs to do. Arguably the government could decide to raise income tax a bit here or reduce VAT a bit there , etc, but it would not have complete control of fiscal policy as it now does.
This is not my favoured option BTW. But, if the pilot is going to hand over the (macroeconomic) controls to his or her co-pilot it should be all the controls and not just one.