According to a recently-released report by the U.S. Centers for Disease Control (CDC), the fertility rate in America in 2023 fell to 1.62 births per woman, the lowest rate since 1979. The dearth of fecundity in this country is well below the replacement rate of 2.1 births per woman, the level required to maintain a stable population. 

Why should we care about fertility rates, and what do they have to do with foreign policy, this writer’s primary area of academic focus? Any significant, sustained divergence from the replacement rate in a society’s fertility rate potentially presents mid- to long-term economic, political and security challenges to that nation. Let’s look at some real-world examples to support this claim.

In the realm of underpopulation, many countries in the developed world are decreasing in population while simultaneously rapidly aging. Take Japan, for instance, which has a fertility rate of 1.3 births per woman, and a median age of almost 50, among the highest in the world. That means a rapidly decreasing number of working-age adults providing the tax base to care for an ever increasing number of senior citizens, The result is a society demographically out of balance with implications for the country’s ability to compete economically, field a deterrent military force to counter China in the East China Sea and care for a ballooning senior citizenry. 

Japan, however, is not alone, as many other developed nations – South Korea (fertility rate 0.81), Spain (1.29) and Italy (1.3), to name a few – face serious threats to their futures barring a major increase in fertility or accepting potentially socially disruptive, large-scale immigration. Even China, until recently the most-populous polity on Earth with 1.4 billion citizens, is confronted with an exploding aging population and a fertility rate that has not reached the 2.1 replacement rate in over 30 years, in large part due to the enduring, self-inflicted consequences of the onerous one-child policy. President Xi is painfully aware of this troubling, long-term trend, which could impel him to move on Taiwan sooner rather than later, before the Middle Kingdom’s inexorable population decline starts to degrade its economic vitality and military might. 

Demographic warning signs are blinking red as well in other parts of the world for the opposite reason, overpopulation. One only has to look at the Sahel region of Africa, the group of countries stretching from Mauritania on the Atlantic coast to Sudan on the Red Sea. These nations, occupying the geographic transition zone between the Sahara Desert in the north and the continental tropics to the south, boast some of the highest fertility rates in the world, many over six births per woman. The ensuing population stresses, combined with climate change-induced agricultural degradation and escalating terrorist activity, have resulted in a series of military coups across the region in Mali, Burkina Faso, Niger and Chad. 

Russia has quickly cozied up to the new autocratic rulers, in the process supplanting longstanding French and U.S. influence across the Sahel.

 More worrisome for Western countries, particularly in Europe, is mass migration from politically unstable regions in the global south which are burdened with overpopulation, dangerously susceptible to climate change and facing persistent terrorist threats. Expect in the coming years that many of these downtrodden masses will vote with their feet, creating for the Old World a prospective immigration nightmare that will stress the unity of the European Union and make America’s current woes at the southern border seem like child’s play. 

Meanwhile, back in America, while our fertility rates remain distressingly low, our population outlook compared to much of the rest of the world is less dire, primarily due to a steady influx of newcomers, both legal and illegal. Consequently, to ensure that we maintain a demographic balance necessary for a secure and economically viable future, sensible immigration policy will need to be part of the way forward. Accomplishing that, unfortunately, may well prove more difficult than raising this country’s fertility rate. 

Robert Beck of Peterborough served for 30 years overseas with the United States government in embassies in Europe, the Middle East and Asia. He now teaches foreign policy classes at Keene State College’s Cheshire Academy for Lifelong Learning.