Should monetary policy never again become more restrictive?

In recessions and crises, central banks (we look at the cases of the United States and the euro zone) conduct increasingly expansionary monetary policies to stimulate demand and also to enable governments to conduct highly expansionary fiscal policies. The expansionary monetary policies then lead to rapid increases in the prices of financial and real estate assets. This has led to calls for central banks to make monetary policy more restrictive in expansion periods ( to “lean against the wind”) in order to avoid giving rise to asset price bubbles. But many studies have showed that lean ing against the wind to prevent bubbles is a mistake : such a policy weaken s the economy and, moreover, trigger s financial crises instead of preventing them. If we followed these studies, monetary policy would be highly expansionary during recessions and would remain expansionary during expansion periods. It would never again be restrictive. See, for example, L. Svensson (2017), “Cost-Benefit Analysis of Leaning Against the Wind”, Journal of Monetary Economics vol 90. M. Schularick, L. Ter Steege, F. Ward (2020) “Leaning Against the Wind and Crisis Risk” CEPR Discussion Paper 14797, May