While the conflict is largely quiet and out of public view, we are in the midst of an epic battle for the soul of the financial system. Central banks are thinking about whether they should substitute publicly issued digital currency for the bank-issued digital money that people use every day. How this plays out can profoundly reshape the financial system and make it less stable.

The forces driving government decisions are unusual because there is a widespread fear of losing an emerging arms race. No one wants to face plunging demand for their currency or surging outflows from their financial institutions should another central bank introduce an attractive new means of exchange. But that pressure to prepare for the financial version of military mobilization can lead to a very unstable global system that thwarts monetary control.

Central bank digital currency (CBDC) can take many forms. While some may be benign, the most radical version—one that is universally available, elastically supplied, and interest bearing—has the potential to trigger destabilizing financial shifts, weaken the supply of credit, and undermine privacy….