Fertility rates below replacement level are widely considered to be detrimental to national power. If such rates are accompanied by an overall population structure in which older people outnumber younger people, what was detrimental becomes an impending catastrophe. These prevalent beliefs would benefit from more critical scrutiny.
That demographics are relevant to a state’s power is not up for debate. Whether an aging population is indicative of future weakness, however, is a question worth considering. In the 20th century, population structure was actually a relatively weak predictor of national power. Germany in 1933 worked itself into a violent hysteria over fears that population decline spelled national decline. Then it nearly conquered Europe. Moreover, predicting the future age and fertility of a population proved almost impossible for most demographic experts of the 20th century. In the 1960s, American demographers feared overpopulation; by the late 1970s they w