“Reformers are famously prey to the fanaticism of reform. A sense of indignation and a good cause lead first to moral urgency, and then soon afterward to repetition, whereby the reformers become captive to their own rhetoric, usually at a cost to their cause. Crusaders against widespread alcoholism (as acute a problem in 1910 as the opioid epidemic is today) advanced to the folly of Prohibition, which created a set of organized-crime institutions whose effects have scarcely just passed. Progressive Era trade unionists, fending off corporate thugs, could steer into thuggish forms of Stalinism. Those with the moral courage to protest the Vietnam War sometimes became blinded to the reality of the North Vietnamese government—and on and on. It seems fair to say that a readiness to amend and reconsider the case being made is exactly what separates a genuine reforming instinct from a merely self-righteous one.”