In the winter of 1964, Daedalus, the journal of the American Academy of Arts and Sciences, published a collection of articles titled “A New Europe?”

The contributors assumed that the question was rhetorical. By the mid 1960s, it seemed obvious that a stable, prosperous new Europe had arisen from the ruins left by decades of war, political unrest, and economic upheaval. There were still problems to be faced, of course, but the most important fact about the Europe of 1964 was how it had managed to overcome the destructive violence of a still-very-recent past.

As we enter the twenty-first century’s second decade, questions about a new Europe have a very different valence. No longer a welcome escape from a terrible past, the possibility of a new Europe now suggests an uncertain, perhaps menacing future. At the same time, the weight of the question has shifted to the notion of Europe itself, to the survival of European culture and historical identity. Some have begun to wonder if “Europe” even has a future.

Let us begin thinking about this future with the problem of demography, which measures those millions of individual births and deaths and migrations that, taken together, define a population. Demography is not destiny, it does not determine the future, but it does reflect those deep social and cultural trends that limit the range of future possibility. In the middle of the eighteenth century, modern European history began with a dem-ographic revolution, in which millennia of sluggish population growth, often broken by catastrophic downturns, gave way to an era of accelerating expansion. Between 1800 and 1900, Britain’s population increased from 11 to 37 million, and Germany’s grew from 23 to 56 million. In complicated, still somewhat mysterious ways, this demographic transformation helped create the urban, industrial, and democratic revolutions that we associate with modernity.

Europe’s population growth slowed in the early twentieth century, as people took advantage of improved means of contraception to limit the size of their families. The full impact of these changes was blunted in the three decades after the Second World War when a decline in the birth rate meant that a larger proportion of the population was in the active work force. This was, not surprisingly, a period of extraordinary productivity and prosperity. Increasingly, however, the contours of a new demographic regime became apparent. First, at 1.5 births per female, the European fertility rate is now well below the replacement level (usually calculated at 2.1); in the long run, this will mean a contraction of the population. Second, and equally important, at the same time that the number of births declined, there were dramatic improvements in life expectancy. This means that the relative size of the oldest age cohorts will become larger and larger. In Italy, for example, the sector of the population over the age of sixty-five grew from 13 percent in 1950 to 24 percent in 2005; it is estimated to be 41 percent by mid-century.

We cannot predict the social, political, and cultural consequences of this new demographic structure. It is hard to imagine what it will be like to live in a society where people over eighty outnumber children under fifteen. It is less difficult to foresee the kind of strains that will occur when an ever-increasing number of pensioners require support from a steadily shrinking workforce: in Western Europe, the cost of public pensions is projected to grow from 10 percent to 20 percent of GDP between 2005 and 2050. The number of active workers, on the other hand, will decrease, perhaps by as much as 20 percent. There is, therefore, good reason to think that when what the Economist recently called the “silver tsunami” hits, age may replace class and nationality as the most important source of social conflict.

Demographic change will also have an impact on Europe’s international position. In the nineteenth century, Europe’s population growth had been both the precondition and the product of Europe’s extraordinary global influence. As the Oxford historian John Darwin recently noted, to understand British power in the great age of empire, we should keep in mind not only the Royal Navy and pound sterling but also what he calls the “demographic imperialism” that dispatched millions of immigrants to the United States and to settler colonies around the world. In 1900, Europe accounted for almost a quarter of the world’s population; by 2005, only about 7 percent. No member of the European Union is now among the twelve largest countries in the world. In 2050, Europeans will be less than 5 percent of humanity, and the most populous European nation, Germany, will rank only twenty-sixth in the world.

The relative decline of Europe’s population has a special meaning for Catholicism because it signals the end of a long historical era in which the church was fundamentally shaped by European culture and politics. For more than a millennium, the Catholic Church was run by Europeans, largely in response to European problems and possibilities. As late as 1950, Europeans made up 49 percent of the world’s Catholics, 76 percent of priests, and 64 percent of seminarians; fifty years later, these figures had declined to 27 percent, 52 percent, and 24 percent. Of these numbers, the most significant is obviously the last, which points toward a future in which a growing majority of priests and then of bishops and then of cardinals will come from outside the traditional Catholic heartland. Benedict may not be the last European pope, but he may well be the last pope whose life and thought is deeply rooted in the European past and present.

The waning of European Catholicism is, of course, not merely the result of demographic decline; it is also tied to a massive contraction in Christian affiliation, which is most dramatic among Northern European Protestants, but has also powerfully affected Catholics, even in such redoubts of traditional piety as Ireland and Poland. The dechristianization of Europe, deplored or applauded as imminent since the eighteenth century, seems finally to be here. This brings us to the second powerful engine of change in the new Europe: the cultural, social, and political impact of immigration in general and of Islam in particular.

Migration has always been part of European history. For centuries, millions of people, sometimes freely, sometimes involuntarily, moved across the continent, fleeing poverty and oppression, searching for opportunity and security. We should remember that immigration is usually the product of grim necessity; few people leave home because they want to, and many return if they have the chance. The immigrant’s choice is not between some cozy rural cottage and the fetid slums of an industrial city, but between privation and survival—in the nineteenth century this was the choice between the barren fields of a place like Connemara and the tenements of Boston or Manchester. After 1945, people continued to flee Europe’s impoverished periphery—Spain, the Italian South, Greece—to its increasingly affluent center. But in the postwar era, for the first time in modern European history, immigration involved a substantial and growing number of non-Europeans, some of them citizens of Europe’s former colonies, others “guest workers” invited to meet the labor shortages created by Europe’s booming economy. In the mid-seventies, when the economy cooled, most European states began to raise barriers to immigration, but by then it was too late. The size of “non-European” communities continues to grow, in part because their birth rates remain substantially higher, and in part because of an influx of family members, successful applicants for asylum, and an unknown number of illegal aliens.

It should be emphasized at the outset that a great deal of what we are told about European immigration is contested, distorted, or simply wrong. Accurate information on immigrants’ attitudes and behavior is hard to get, which opens the door to shoddy journalism and political exploitation. It is even difficult to know just how many “non-Europeans” there are now living in Europe. Estimates on the number of Muslims, for example, range from 13 to 20 million. It is clear that recent immigrants tend to be concentrated in a few large cities, where they sometimes make up a quarter of the population and, in a few cases, more than half. This concentration may be one reason why so many people greatly overestimate the number of immigrants in their country: the average Briton thinks they make up 27 percent of the population, whereas the actual figure is probably closer to 10 percent.

There is no question that immigration has been attended by some severe social problems, aggravated by structural weaknesses in the European economy. In most countries, immigrants and their offspring are overrepresented among recipients of public assistance, the unemployed, and, most disconcerting of all, those convicted of serious crimes. In Sweden, about 26 percent of those incarcerated are foreign-born, in Italy nearly 50 percent. Dramatic incidents such as the riots that consumed Parisian suburbs in 2005 or the violence that broke out in southern Italy in January 2010 underscore these problems and undermine people’s confidence in the state’s capacity to preserve public order. In a recent poll, 70 percent of Britons, over 60 percent of Spaniards, and more than 50 percent of Italians thought their governments were mismanaging immigration.

From the beginning, many Europeans have viewed the arrival of immigrants with animosity and alarm. In 1968, for example, when British MP Enoch Powell delivered his infamous jeremiad about immigration and evoked the oft-quoted image of rivers flowing with blood, he was fired from his ministerial position but applauded by many ordinary Britons. As the number of foreigners has grown and economic conditions have deteriorated, anti-immigrant sentiment has become louder and more self-confident. Its institutional base remains fairly narrow, but it has on occasion gathered widespread support, as happened last year when 57 percent of the Swiss electorate voted to ban the construction of minarets.

The Swiss referendum, like the current French debate on outlawing the burqa in public places, reminds us that many Europeans identify the social problem of immigration with Islam. Tensions between Europeans and their Muslim neighbors have been aggravated by a cluster of crises in the international system, including acts of terrorism in various parts of the world (including Europe), the wars in Afghanistan and Iraq, the threat of a nuclear-armed Iran, and the apparently endless agony of Israel-Palestine. Self-proclaimed experts in search of readers and politicians in search of constituencies have delivered solemn warnings that Islam is permanently and intrinsically hostile to Western values. This has given the debate over Turkey’s membership in the European Union an added dimension, making it both a question of Europe’s international order and a reflection of deeply rooted domestic antagonisms. Whatever the outcome, the debate itself will surely irritate the relationship between Muslims and other Europeans.

We should never underestimate the dangers that radical Islam poses for the international order, European societies, and—last but not least—other Muslims. And whatever the political, psychological, or social sources of their action, Islamic terrorists claim they are acting in the name of their religion. We must take these claims seriously and not obscure them with pious platitudes or self-serving evasions. But it is equally important not to project the actions of a very small, violent minority onto the Muslim population as a whole. According to a careful study of eleven European cities, recently conducted by the Open Society Institute, a majority of Muslims identify with the cities in which they live, vote when they are eligible to do so, and acknowledge the advantages of living in Europe. Significantly, however, even those who feel most at home in Europe believe that levels of hostility and discrimination against them are rising.

It would be a serious mistake to make Islam responsible for the complex and multifaceted problems of immigration. In the first place, Islamic belief and practice is extraordinarily diverse, both inside and outside Europe. There is, moreover, no reason to assume that Islam is directly related to the incidence of criminality and social unrest among immigrant groups. Immigration almost always involves displacement and anxiety; intergenerational tensions are often part of the immigrant experience, as scores of novels and films clearly demonstrate. Blaming Islam for these deep-rooted problems runs the risk of becoming a self-fulfilling diagnosis.

Even if we acknowledge that Islam may make the assimilation of European immigrants more difficult, remedies are not easily prescribed. The history of anti-Catholicism in nineteenth-century Europe and the United States should make us skeptical about the usefulness of laws designed to restrict or discourage religious practices. (There are, to be sure, some important differences between Catholics and Muslims, but the charges against them—clerical influence, loyalty to alien authorities, the subordination of women—often seem very much alike.) Efforts to ban the wearing of headscarves or the construction of minarets are more likely to increase community cohesion among Muslims and to strengthen the hands of those who wish to sow discord between Muslims and their neighbors than they are to encourage “enlightened” views and political moderation.

The simple, inescapable fact is that Europe’s Muslims, like the rest of its immigrant populations, are not going to go away. Nor will their numbers or their militancy be diminished by largely symbolic laws. Whether they like it or not, Europeans will have to learn to live with their new minorities. In the long run, the road to mutual respect and peaceful coexistence will be provided by greater economic opportunities. For better or worse, the economy is postwar Europe’s most dynamic and effective set of institutions, the primary source of its accomplishments and political values.

In 2010, as in 1964, Europe’s future depends on maintaining and extending the blessings of economic prosperity. It will not be easy. At the moment, the core countries of the European Union seem to have weathered the current economic crisis relatively well, but there are serious difficulties on the periphery (especially, but not only in Greece), which could jeopardize the entire Euro zone. Beyond these immediate threats are the long-term problems of sluggish economic growth and expanding social obligations. No major European government seems ready and willing to address these issues. Indeed, the popular support for most European governments is strikingly shallow. Gordon Brown’s government is probably coming to the end of the Labour Party’s long and increasingly troubled reign. French President Nicolas Sarkozy has never been able to convince many of his countrymen that he is a serious national leader. In Germany, Chancellor Angela Merkel has managed, if not to be popular, at least to avoid being unpopular, largely by postponing hard political choices. And Silvio Berlusconi lurches from scandal to scandal, surviving only because most Italians have long been accustomed to expect very little from their governments.

Nevertheless, we should not overestimate Europe’s problems or underestimate its strengths. A great deal remains of the new Europe created in the aftermath of the Second World War. Europe’s economy is still stable and potentially robust, its societies relatively tolerant and peaceful, its states honest and effective. The danger of a major war, which shadowed the continent as long as the United States and the Soviet Union confronted one another, has disappeared. Much of Eastern Europe, now liberated from Soviet domination and domestic tyranny, is beginning, slowly and unevenly, to share in the prosperity that transformed Western European politics and society. The central task facing the new Europe of the twenty-first century is finding ways to preserve these strengths and deploy them to address the problems of a shrinking, aging, and increasingly diverse society. To do this will require that Europeans turn away from those who preach hatred and despair, and instead draw strength from their achievements and embrace the capacity for tolerance and hope.