The Federal Reserve has kept rates too low for too long. I’m not referring to interest rates. It’s high time for the Fed to raise countercyclical capital-buffer rates, which govern the amount of extra equity and cash banks are supposed to hold in good times. Increasing the capital buffer would reduce the risk of financial instability, set a precedent for sound macroeconomic management, and build up a bigger cushion for the next downturn.

Banking regulation naturally has a pro-cyclical bias. When times are good, there’s a de...