During a crisis, governments often impose new regulations that wind up making things worse when the next crisis strikes from some other direction. The TSA checkpoint system adopted after Sept. 11, for example, is now the one point in air travel where a virus-fearing traveler is least able to avoid prolonged physical or face-to-face contact with a stranger, as well as the handling and commingling of high-touch personal items on communal trays.

Another set of regulations that took off after Sept. 11 was imposed on the financial sector to combat “money laundering” — that is to say, transfers of funds with little or no documentation. Terror groups were portrayed as having a special proclivity for anonymous payments even though all sorts of innocent persons used them too. Under the Bank Secrecy Act, banks must follow cumbersome “know your customer” rules meant to tease out customers’ identities and roles in the economy and also must monitor and report so-called suspicious transactions — anything out of the ordinary for the kind of customer revealed by the profile.