In the summer issue of City Journal, the skeptical doctor revisits an infamous postwar British murder case and the subsequent execution.

Now, a civilized society must put a limit to the severity of a sentence that may in practice be imposed—a threshold above which we cannot go. Someone who kills ten people cannot be punished ten times more severely than someone who kills only one, though the crime, in a sense, is considerably worse. But if the threshold for the most severe sentence is set too high, leniency throughout the system is the inevitable consequence.