Twelve years into a persistent and deepening global democratic recession, it is increasingly clear that the challenges confronting governance in the world are not a passing storm.  As revealed in an eye-opening project on “Governance in an Emerging World,” based at the Hoover Institution and led by former Secretary of State George P. Shultz, profound long-term changes are testing all forms of government.

Most of these transformations have been prominently analyzed. Globalization, with its dizzying accelerations in the movement of people, goods, capital, and ideas, has challenged traditional notions of sovereignty and put a premium on what Shultz has long stressed as a key imperative for national success in our time:  the ability to “govern over diversity.”  Technological change, involving rapid advances in automation, social media, and now artificial intelligence, is profoundly disrupting everything from politics to dating to manufacturing and the workplace.  And climate change is straining the comfort, health, stability, and even viability of many human settlements, to a degree that will increase exponentially in the decades ahead.  These, the New York Times columnist Thomas Friedman has been arguing, are the “three giant transformations” that pause for no one and put a premium on what Friedman called, in his 2018 Compton Lecture at MIT, “learning faster, and governing and operating smarter.”

But as the Shultz project on governance is showing, there is a fourth transformation interacting with these three, one that is no less daunting and, in the short run, little more amenable to alteration: demographic change. To maintain the overall population at its existing size, a society needs an average fertility rate of 2.1 children per woman—what is called “replacement fertility.”  The story of the second half of the twentieth century was astonishingly rapid growth in population throughout the developing world due to improvements in health care but a lag in declining fertility. As a result, according to UN estimates, world population increased from 2.5 billion people in 1950 to 6.1 billion in the year 2000 and about 7.5 billion today.

Global population growth is continuing, but it is slowing and unevenly distributed. Many major countries are now well below the 2.1 level of “replacement fertility.” These include not only most of the advanced industrial democracies—in Asia as well as Europe—but also, stunningly, Russia (1.8) and China (1.6).  The economic and geopolitical ambitions of these two countries will, in the decades to come, run up against hard demographic realities of aging societies and dwindling workforces.  Many industrialized countries now face a similar scenario, never before encountered by human society in an era of peace and abundance: markedly shrinking—and therefore aging—populations. Italy, Japan, Germany, Spain, South Korea, Taiwan, and Singapore are now among the more than twenty countries with fertility rates below 1.5 per woman.

Shrinking populations—especially among the richest countries that use the most resources and therefore emit the most pollution—may sound like a blessing for Mother Nature. And maybe in one sense they will be a blessing for social stability, in that labor forces will be shrinking at just the time that automation will be displacing more and more traditional forms of work. But these demographic transformations will sorely challenge governance in other ways, as there will be fewer and fewer workers to support the rapidly aging populations—while life expectancy continues to lengthen, in some societies (with the revolutions in medicine and biotechnology) quite dramatically.

As Hoover Institution economist and demographer Adele Hayutin has shown in recent research, Japan and Germany already have shrinking workforces, and many other countries are set to follow, including all of the ones with fertility well below replacement. Over the next 20 years, Hayutin estimates, the workforces in Japan and South Korea will shrink by some 15 percent, Germany by 13 percent, and the EU overall by 10 percent (producing 30 million fewer workers in Europe). Part of the shortfall can be made up by increasing employment for women and the elderly (those over age 65). But these societies are all likely to face significant labor shortages.  And it is not just labor as such that is needed. Youth brings innovation and dynamism to a country. There is no social model for societies that will be as old as these industrialized countries will be unless one of two things happens: They dramatically increase fertility, or they import people. Even with economic and social incentives to encourage more births, these societies cannot escape the imperative to welcome precisely the phenomenon against which many advanced democracies now seem to be rebelling: immigration.

One of the fascinating aspects of the global demographic trends is that the United States and Britain face a much more manageable demographic future than most of their industrialized peers. Unlike Germany, Italy, Japan and others, the U.S. workforce, Hayutin finds, will continue to grow in pretty steady fashion for decades to come. In Europe, three countries—Britain, France, and Sweden—defy the larger EU trend. One reason is that they (like the United States) have fertility rates much closer to replacement. Yet their rates are still below it. So how are they making up the difference, and then some?  Immigration.

It is immigration that will give these four societies (and Canada and Australia) economic dynamism, cultural vitality, and greater fiscal sustainability—if they can “govern over diversity.”  The key lies in the traditional American formula, e pluribus unum, out of many one. The imperfect, at times shamefully disappointing, but still remarkable success of the United States in assimilating immigrants while forging the most diverse nation in world history has been an indispensable key to America’s economic and political vibrancy. Will we now squander it in an atavistic and misplaced fear of the “other”, stimulated by demagogues seeking to manufacture fear in order to ride to power? That is one of the key questions confronting the future of the United States and its global leadership.

Yet it is not the whole story. The United States is surprisingly well positioned to absorb and manage immigration. For one thing, we are a nation of immigrants with a history of assimilating successive waves of immigrants. For another, the principal source of immigration across our land border, from Latin America, is expected to decline sharply in the decades ahead. Fertility in Mexico (and in El Salvador) has already fallen to replacement levels, and the undocumented Mexican population in the U.S. has been trending downward since 2008. With planning and rational policy (such as keeping highly educated workers in the United States once they finish their science and engineering degrees), the United States could continue to dominate all its competitors in the new global economy of high technology. Industrialized Asia—Japan, Korea, Taiwan, and Singapore—needs this immigration even more, but save for Singapore, these countries lack a strategy for recruiting and absorbing it.

However, it is Europe that faces the stiffest challenge. Barring some miraculous reversal in fertility trends, the EU will need to import significantly more young workers if it is going to be able to support its burgeoning population of elderly. Where will these young workers come from?  In theory, the source could be any number of emerging market countries where the working age population (15-64) is slated to grow in the next twenty years, including India (whose labor force stands to growth by a quarter in the next two decades). Egypt, Pakistan, and the Philippines will also see continued rapid growth in their working age populations. But far and away the largest share of population growth will come in sub-Saharan Africa, where the labor force will nearly double in the next twenty years, adding over 400 million people.

The juxtaposition of Europe’s population implosion and Africa’s population explosion will make for one of the most important social and political trends of the coming decades. The problem goes far beyond the simple arithmetic logic of migration. As James Kirchick writes in an essay for the 2019 “Great Decisions” program of the Foreign Policy Association, current levels of immigration to Europe, especially from Africa and the Middle East, have fed the rapid growth of right-wing, nativist populism even in healthy economic performers like Germany, Poland, and Sweden. In the past five years, Sweden (a country of ten million) has welcomed over half a million (mostly less well educated) migrants, who, Kirchick reports, have been disproportionately involved in a rising tide of violent crimes. As a result, political support for the Sweden Democrats, a right-wing, anti-EU party with neo-Nazi origins, has more than doubled since it first entered parliament in 2010, making it the country’s third largest party (as is the far-right Alternative for Germany in that country). Even liberal and tolerant societies have a limited capacity to absorb new people from diverse places and cultures. As has historically been the case in the United States, the warning signs of political reaction start flashing red when the percentage of foreign born reaches well above ten percent.

So the EU—and Japan, and other industrialized countries—are going to need a much more strategic and intentional strategy for encouraging, screening, training, placing, and absorbing more highly educated immigrants at a manageable pace over an extended period of time. But tell that to poor young men with limited education from Africa and the Middle East who feel trapped by poverty, joblessness, and violent conflict, and who—like many Mexicans historically—are determined to head north for a better life. The numbers are staggering. Africa is set to add over a billion people between 2015 and 2050, with its total population increasing to over 2 billion. Many African countries, sociologist Jack Goldstone has shown for the Shultz project, will reach staggering numbers by 2050: over 400 million Nigerians, nearly 200 million Ethiopians, over 100 million Ugandans. And these increases will come at the same time that climate change (and population growth itself) increasingly disrupt agriculture, water supplies, disease vectors, wildlife habitats, and thus the increasingly lucrative tourism industry.

There is a way out of impending disaster: vigorous and broadly distributed economic development, which lifts the skill levels of African populations and enables them to contribute productively to economic growth both in their own countries and in the aging societies to which they emigrate. This could generate something of a virtuous cycle, because nothing brings down the fertility rate like rising levels of education and employment for women.

“If by 2050,” Goldstone concludes, “Africa can turn the corner on fertility and reduce its population growth,” while investing in human capital and physical infrastructure, “then in the second half of this century Africa could be the main motor of global economic growth, much as China has been for the last thirty years and India could be for the next thirty.” But that won’t be possible without dramatic improvements in the quality of African governance to stem corruption, strengthen the rule of law, and create an enabling environment for investment and innovation.  Today, there is no regional or global strategy to support and induce these improvements in governance. Rather, there is a new great power scramble for Africa’s resources and markets, with China—which couldn’t care less about the rule of law in Africa—the most audacious player.  This picture must change, dramatically and soon, or the world will lose a historic opportunity to bring demography into balance with a minimum of conflict.