LifeNews.com Note: Nicholas Eberstadt is the Henry Wendt Scholar in Political Economy at the American Enterprise Institute.

The concept of "American exceptionalism" has been applied mainly to the political differences that separate the United States from the "Old World": the striking absence of any serious American socialist movement; the spirit of Manifest Destiny informing its foreign policy, and so on. But America's exceptionalism extends beyond the explicitly political and into the nation's very rhythms of birth and death. These rhythms constitute what may be described as American demographic exceptionalism.

Paradoxically, although the United States may well count as the "first new nation" (to borrow a phrase from the late Seymour Martin Lipset) to embark upon the project of democratic modernity, U.S. demographic patterns have not conformed to those of the world's other industrial democracies. On the contrary: After several decades of seeming convergence in population patterns in the early post-World War II era, we have witnessed more than a generation of strong and stubborn "demographic divergence" in population profiles between the United States on the one hand, and virtually all other OECD countries, on the other. And there are potentially even more dramatic divergences in store.

Two demographic tendencies separate the United States from virtually all other developed countries in Europe and Asia. The first is childbearing patterns: At a time when most rich countries report markedly low birth rates, U.S. fertility levels are close to long-term population replacement levels, making the United States peculiarly fecund for a contemporary affluent democracy. The second is immigration patterns: America's absorption of foreigners continues apace, with high and continuing inflows of immigrants from the Third World, but without (as yet) the symptoms of cultural indigestion that have lately troubled much of the European Union.

America's demographic exceptionalism would be a fascinating academic sidenote if the United States were today a tiny state, distant from the core of global power, as it was in 1790. But the United States is now the world's dominant power, as well as the most populous developed society: more than twice as large as Japan, three times as large as Germany and five times the size of France, Italy or Britain. America's exceptional demographic trends are therefore of interest not only to demographers and sociologists, but also to economists, strategists and policymakers looking at the international environment that awaits coming generations.

The Facts

From its earliest Colonial origins, childbearing was believed to be markedly higher in this frontier society than in the settled regions of Europe whence most Americans traced their roots. This American fertility premium was noted and discussed by leading thinkers on both sides of the Atlantic--Malthus in Britain, Crиvecoeur in France and Benjamin Franklin in America (who reportedly offered the vision of Americans "swarming across the countryside like locusts").

Those perceptions were grounded in demographic reality. The U.S. Bureau of the Census estimates a "total fertility rate" (TFR) in 1800 for America's whites of more than seven births per woman per lifetime, compared with contemporaneous rates of about 5.7 in England and 4.5 in France. Fertility levels were even higher for African-American slaves; the black TFR for the 1850s was nearly eight--a level more than 40 percent higher than for contemporary U.S. whites.

From this exceptionally high starting point, the United States moved more or less steadily over the course of the 19th century through a demographic transition toward lower death and birth rates. By 1900, the United States was the world's most modernized and affluent large country (excepting only Britain ), and with its white TFR by then down to 3.6, its fertility transition had progressed further than it had in most of its European counterparts (again, excepting England, as well as France).

After World War II, in the era of the developed world's baby boom, U.S. fertility levels once again jumped above Europe's. According to the UN Population Division, America's TFR in the 1950s was over 3.5, whereas Europe's was under 2.7--just three-fourths the U.S. level. But in the pervasive "baby bust" that followed, U.S. fertility declined even more sharply than Europe's, dropping to levels that, had they continued, would have presaged steady population decline in the absence of immigration. By 1976, America's "period" TFR was 1.74--lower than the fertility level of the EU--15 that same year, less than half of America's own level from the late 1950s and 18 percent lower than the requirements for longterm population stability.

At that juncture, standard-issue modernization theory seemed triumphant: Socio-economic development appeared to have brought about a basic convergence in fertility trends (at sub-replacement levels) for the world's developed regions. But a funny thing happened on the road to depopulation: America's fertility levels turned upward, and then persistently skirted replacement level. In 1989, America's period TFR rose slightly above two and has remained in that neighborhood ever since. In the 16 years from 1989 to 2004, America's TFR averaged 2.02 births per woman, suggesting a net replacement rate (NRR) of 98 percent from one birth cohort to the next.

America's limited but unmistakable fertility upsurge over the past generation marks a striking departure from trends for almost every other developed society. In the first half of this decade, according to UN Population Division projections, America's TFRs and NRRs were fully 50 percent higher than Japan's and about 45 percent higher than averages for Europe as a whole. Europe's overall fertility levels, to be sure, may currently be depressed by the post-communist demographic shocks that some former Soviet bloc countries (most notably Russia) in eastern Europe continue to experience. But even compared with the amalgam of west European societies, the U.S.-European fertility gap now looks like a yawning chasm. America's recent fertility trends have even opened a divide between the United States and Canada, countries that have long been regarded as demographic "twins." In 2004, the TFR in the United States was 35 percent higher than in Canada (with a still greater differential separating the United States and French-speaking Quebec province).

How can we explain the fertility gap now separating the United States from practically all the rest of the developed world? Experts worldwide have already begun to discuss two uniquely American social phenomena: first, America's increasingly multiethnic composition (due in large measure to high rates of net immigration), and second, the partly related phenomenon of American teenage fertility levels, which are famously high in relation to other contemporary affluent democracies. Yet however plausible such factors may sound, they cannot fully explain the gap.

Consider teenage childbearing patterns: Although America's high rates may be notorious within today's OECD societies, the fact is that U.S. teenage birthrates fell by about a third between 1990 and 2004, even though the overall U.S. TFR remained relatively high and steady. By 2004, moreover, teen births comprised just a tenth of all American births and about a tenth of America's overall TFR. In practical terms, that means that a total cessation of childbearing by women under twenty years old would still leave U.S. fertility levels more than 20 percent higher than western Europe's.

As for fertility differences by ethnicity in the United States, these are real enough, but it is easy to exaggerate their significance. With the single, albeit highly significant, exception of Hispanic Americans, fertility levels for U.S. minorities have largely been converging with the non-Hispanic majority. Indeed, average fertility levels for Asian Americans are almost identical to those for "Anglo" Americans, and Native American levels are now lower. While birth rates remain higher for African Americans than for Anglos, the current black-white differential (just 9 percent) is now the lowest it has been since the slavery era. The Hispanic-Anglo fertility gap, for its part, is mainly a matter of the high reported birth levels for Mexican Americans (whose calculated TFRs currently touch three). Some other Hispanic Americans register fertility levels fairly close to Anglo levels (for example, Puerto Ricans), or below them (Cuban Americans).

The single most important factor in explaining America's high fertility level these days is the birth rate of the country's Anglo majority, who still account for roughly 55 percent of U.S. births. Over the past decade and a half, the TFR for non-Hispanic white Americans averaged 1.82 births per woman per lifetime--subreplacement, but more than 20 percent higher than corresponding national levels for western Europe, and much higher if one compares "Anglo" TFRs with those of western Europe's native born populations.

The Reasons

What accounts for Anglo America's unexpectedly high and stable propensity to reproduce? Carefully tailored pro-natalist government policies certainly cannot explain it: The United States has none. By the same token, U.S. labor patterns do not seem especially "family-friendly." Americans work longer hours and enjoy less vacation time than any of their European friends across the Atlantic, and none of the economic or policy explanations for the growing fertility gap between U.S. Anglos and west Europeans offers a satisfying explanation.

The main explanation for the U.S.-Europe fertility gap may lie not in material factors but in the seemingly ephemeral realm of values, ideals, attitudes and outlook. Public opinion surveys, for example, have thoroughly established that Americans tend to be more optimistic about the future than Europeans--a disposition that could weigh on the decision to bring children into the world. Similarly, more Americans report being "proud" of their country than do Europeans, which, quite plausibly, could lead to more births. All else equal, patriotism or nationalism may conduce to higher birth rates. Most portentously, perhaps, survey data indicate that the United States is still in the main a believing Christian country, with a high percentage of households actively worshipping on a monthly or weekly basis. In striking contrast to western Europe, which is often provocatively (but not unfairly) described as a post-Christian territory these days, religion is alive and well in the United States.

It is not hard to imagine how the religiosity gap between America and Europe translates into a fertility gap. Unfortunately, the proposition is devilishly difficult to test. Although the United States is (in Pitirim Sorokin's term) a "quantophrenic" society, hungry for all manner of facts and figures, a more than three-decadeold Federal law expressly forbids the U.S. Census Bureau from posing questions to the citizenry about religious affiliation. This specific stricture has evolved into a broader general operational posture within the U.S. Federal statistical system that information on the religious beliefs of U.S. citizens should only be collected, if at all, under truly exceptional circumstances. Consequently, there are virtually no official national data for the United States that would permit a rigorous testing of the hypothesis that America's religiosity is directly related to its childbearing. Attempts to connect those two factors on the basis of broad, aggregate observations and trends run the risks of committing what statisticians call the "ecological fallacy"--mistakenly associating two unrelated phenomena for want of examining relationships at the individual level. For the time being, at least, this proposition must remain a speculation.

The United States has historically also been and remains a nation populated overwhelmingly by immigrants. Immigration, both legal and illegal, remains a central feature of the country's demographic life. The 2000 census count hinted at the scale of illegal immigration by noting that there were six million more residents than the "intra-census projection" had prepared U.S. officials to expect.

Western Europe has experienced its own influx of newcomers over the past generation, but in both relative and absolute terms the influx of migrants to the United States has significantly exceeded the European influx. U.S. Census estimates and projections place net migration into western Europe over the past decade (1996-2005) at roughly 740,000 persons a year, about 1.9 migrants per thousand of the settled population. The corresponding U.S. figures are about 980,000 a year and a rate of 3.5 per thousand. Some developed societies have net immigration rates today that are higher than America's--Australia, Canada and New Zealand, for example. But no large country today (defined as having at least fifty million people) has a rate even close to that of the United States. While the United States accounts for a fourth of the population of the so-called "developed regions" (including east-central Europe and Russia), it accounts for nearly half of the area's annual net migration.

In purely arithmetic terms, America's high flows of net immigration do explain much of the country's steady population growth. Currently, about a third of the U.S. annual demographic increase can be attributed to net immigration, but new descendants of immigrants account for an even greater share of that annual change. In fact, depending upon how far back we set the benchmark, we could ascribe virtually all U.S. population growth to immigrants and their progeny. A good benchmark would be 1965, the year when U.S. immigration laws were thoroughly liberalized and much higher and more geographically diverse quotas superseded the restrictive legislation of 1924.

Estimating the precise proportion of U.S. population growth since 1965 due to immigrants and their descendants is a little trickier than one might think, however. To my knowledge, no published work has attempted it. Jeffrey Passel of the Urban Institute suggests in unpublished estimates that about 53 percent of U.S. population growth since 1965 can be broadly ascribed to immigration. America's population has grown by more than 100 million over that period--from about 194 million in midyear 1965 to just over 300 million at present--this means that post-1965 immigrants and their descendants account for well over fifty million Americans, or more than a sixth of its residents.

The foreign-born population of the United States is now more than 33 million, nearly 12 percent of the total. In many urban areas, the proportion of immigrants is considerably higher. The 2000 census, for example, found that 22 percent Chicago's population was foreign- born. Corresponding proportions exceed 30 percent for Boston, 35 percent for both New York and San Francisco, and 40 percent for Los Angeles. Since less than a fifth of these migrants originated from Europe, Canada or Australia, America's new wave of immigration is overwhelmingly non-European. More than a fourth of America's foreign born, for example, now come from Asia. An estimated 52 percent of the newcomers are Latin American, with Mexican-born immigrants accounting in turn for the majority of these Latinos. The Census Bureau estimates that more than nine million Mexican-born men, women and children live in the United States today, more than half of them illegally.

America's latest wave of immigration has certainly exacerbated certain domestic tensions. Certainly, it has stimulated an undeniable measure of "nativist" political backlash. (Witness the law passed last October for erecting what would be the world's largest fence, a gigantic 700-mile barrier along the U.S.-Mexico border, and continuing proposals to seal off the rest of the border as well.) Furthermore, post-9/11 America now views the idea that seven million or more people have entered the country illegally through the prism of national security.

Yet when all is said and done, America's new immigrants are assimilating tolerably well, in the pattern of earlier historical migrations to the United States. Despite the high concentration of relatively poor, and poorly educated, immigrants in big cities, America's urban areas have not become tinderboxes for violent unrest by the foreign-born, unlike contemporary Europe. Furthermore, despite alarums that "some" immigrants (code language for Mexicans) are failing to assimilate or are positively resisting assimilation, the evidence points in the opposite direction. (A recent study in Southern California, for instance, suggests that Spanish-speaking at home among Mexican Americans declines steadily from one generation to the next, at a pace similar to the decline of foreign "kitchen talk" in America's highly successful Korean and Chinese immigrant communities)

The United Sates has experienced anti-immigrant paroxysms in the past (such as the one resulting in the 1924 Immigration Act). Economic historian Jeffrey G. Williamson has argued that the last great U.S. crackdown on immigration was decades in the making, bringing to a flashpoint tendencies that had been gathering from the 1890s. This was an era, Williamson recalls, characterized by rising economic differences, high volumes of migration, significant pressure on wages for low-skilled native-born Americans, and gradually increasing political calls for immigration restrictions. In this earlier era, Williamson argues, America's radical immigration rollback was finally catalyzed by a "triggering event"--namely, World War I. Williamson's analysis is compelling precisely because so many of those same social, economic and political tendencies are gathering in the United States today. It thus begs the question: Could a new triggering event lead to a similar anti-immigration policy?

The Future

American fertility and immigration trends cannot be forecast with any great accuracy over the coming generation (nor can they be for any other developed country). However, if American demographic exceptionalism continues for another decade or so, the consequences could be truly profound.

Just what such exceptionalism would portend may be seen by comparing U.S. Census Bureau projections for the United States and western Europe for 2025. These projections assume a gradual improvement in life expectancies in both regions. More critically, they posit an increase in both west European and American TFRs (to 1.62 and 2.18, respectively, in 2025) and a slight absolute decline in average annual net migration for both regions (to about 700,000 and 900,000, respectively). Some reputable demographers quibble with these assumptions (the United Nations Population Division's "medium variant", for example, envisions that U.S. TFR will drop below 1.9 by 2025). In any case, these projections vividly illustrate the longer-term implications of continuing American demographic exceptionalism.

In demographic terms, western Europe and the United States would be strikingly different places two decades hence. Western Europe's total population would be shrinking despite continuing immigration, while America's would still be growing by about 2.8 million a year. Western Europe would be much "grayer" than the United States, with a median age of 46 years (as against 39 years) and nearly 23 percent of all people 65 or older (versus 18 percent in America). In this future, children under 15 would make up just a seventh of western Europe's population, but nearly a fifth of the U.S. population. Senior citizens (65 and older) would outnumber children (under 15) in western Europe by a ratio of roughly 1.6 to one, while the United States would still have more children than seniors.

Although western Europe's total population would still exceed America's by around fifty million in absolute terms (400 million versus 350 million), all of that differential would accrue from older age groups (fifty and older), with the balance weighted especially toward septuagenarians and octogenarians. For the under-25 population, on the other hand, Americans would outnumber west Europeans.

America's prospective demographic divergence will affect not only Europe, but the entire developed world--and indeed beyond.

By these same Census Bureau projections for 2025, America's population growth rate would be the highest among the more developed regions, and America's median age, apart from fascinating exceptions like Albania, would rank toward the bottom. The United States would also be the only developed country of more than fifty million people with more children than senior citizens, and the only developed country at all whose working-age population (15-64) would be growing.

Moreover, America's population trends presage a demographic divergence not only with western Europe, but also China--the nation widely regarded as today's leading contender for rising global power. Thanks to decades of sub-replacement fertility--a consequence at least in part of Beijing's relentless and coercive birth control program--China's population growth stands to decelerate sharply, and its society to age dramatically, over the coming generation.

Under current projections for the year 2025 the United States looks to be a more youthful country than China by such criteria as median age. In 2025, furthermore, China's 15-64 labor force will have been shrinking in total size for more than a decade; the corresponding U.S. manpower pool is expected to be increasing, albeit modestly. Perhaps even more striking, population projections by both the U.S. Census Bureau and the UN Population Division envision the absolute annual population growth of the United States to exceed China's by 2025.

To the extent that population structure influences economic performance, America's exceptional demographic profile could confer developmental advantages on U.S. society. All else equal, America's relatively youthful population should experience less pressing burdens from pension and health costs in the years ahead than the rest of the world's more elderly developed democracies. A growing labor force offers opportunities for innovation, start-up and reallocation of productive resources that a declining workforce does not. The best-educated elements of any developed country's workforce tend to be the youngest entrants, but while that group stands to shrink in relative and absolute terms throughout the developed world as a whole over the next two decades, America's pool of young manpower will almost certainly continue to grow.

Beyond population composition, absolute numbers also matter in international affairs. America's aggregate population size has an incalculable but nonetheless genuine bearing on the country's global predominance today. The United States is the world's third-largest country (after only China and India), and projections suggest it will remain number three in the next few decades.

With its exceptional and robust projected population growth, America is also poised to account for an increasing share of the total population of the present developed countries. Whereas the ratio of Americans to Russians today is a little more than two-to-one, by 2025 that ratio may be almost three-to-one. There are 3.6 Americans for every German today; there will be 4.4 per German in 2025. There are five Americans for every Italian today; there will be six per Italian in less than two decades. And so forth. Such trends might reinforce U.S. international predominance, even though the divergence in demographic profiles between the United States and the rest may also portend an era of diminishing affinities between the United and its historical Western allies.

Assessing the implications of such unfolding trends is, of course, speculative. But as these projections show, U.S. demographic exceptionalism is not only here today; it will be here tomorrow, as well. It is by no means beyond the realm of the possible that America's demographic profile will look even more exceptional a generation hence than it does today. If the American moment passes, or U.S. power in other ways declines, it won't be because of demography.