Eighty years ago, Germany’s former conquerors rejected wrecking the defeated nation as too harsh. But now Germany is willfully pastoralizing, disarming, deindustrializing—and destroying—itself. Less than a year before the end of World War II, then U.S. Secretary of the Treasury Henry Morgenthau drew up a nightmarish plan to punish postwar Germany. After the serial 1870-1871 Franco-Prussian War, World War I, and World War II—along with the failed Versailles peace treaty of 1919—the Allies in World War II wanted to ensure there would never again be an aggressive Germany powerful enough to invade its neighbors. When the so-called Morgenthau Plan was...