Harold Macmillan, a British prime minister of the 1950s and ’60s, was reputedly asked what made his job most difficult, and he replied, “Events, my dear boy, events.” This echoed his wartime boss, Winston Churchill, who once commented that he governed against “the opposition of events.”

Having a quiver full of plans, even unworkable and damaging ones, as so many Democratic plans are, is the easy part of governing. A much tougher test is how you handle unforeseen difficulties as they arise, whether they come from third parties beyond one’s control or flow naturally from one’s own utopianism and incompetence. Joe Biden is suddenly getting a dose of both.