The scarcity we are observing is not a traditional currency scarcity. As such, we can’t correct the scarcity by using conventional central banking tools – open market operations in short-term government debt and discount window lending. Neither can we correct it through “quantitative easing.” We cannot ease anything through swaps of reserves for long-maturity debt, as that cannot make reserves relatively less scarce under the current circumstances. But the inability of monetary policy to correct the liquidity scarcity problem has nothing to do with the zero lower bound on short-term nominal interest rates, as the key problem is a contemporary liquidity trap, not Grandma’s liquidity trap.
How can government action mitigate the liquidity scarcity? If monetary policy cannot do it, that leaves fiscal policy. But there is a tendency, particularly in the blogosphere, to frame the problem in Old Keynesian terms. In this view, we are facing Grandma’s liquidity trap, the LM curve is flat, monetary policy doesn’t work, so shift the IS curve instead. Further, unemployment is very high and persistent, so it might seem natural to have the government employ people directly by spending more. But the problem here is financial, and it’s not a Keynesian inefficiency associated with real rates of return being too high; in fact real rates of return are too low given the scarcity of liquid assets, which produces large liquidity premia.
One way to solve the problem would be to have the Treasury conduct a Ricardian intervention, i.e. issue more debt with the explicit promise to retire it at some date in the future. If the future arrives, and we still have a scarcity, then do it again. This requires a transfer, or a tax cut in the present, and leaves the present value of taxes unchanged, but the result is not Ricardian because of the exchange value of the government debt issued.
Here is more, and you can take this post as a validation of many (not all) of the broader methodological points Williamson likes to make. “Neoclassical macroeconomics” is not totally out to lunch, and it is ignored at our peril.