In a world in which almost any subject seems to arouse deep cleavages within and among countries, arguably the one that has today the deepest and geographically widest resonance is migrants. At the moment, the most acute locus of attention is Europe, where there is a vociferous debate concerning how European countries should respond to the flight to Europe of refugees, especially those from Syria but also those from Iraq and Eritrea.

The basic argument in European public debate has been one between the advocates of compassion and morality who wish to welcome additional migrants and the advocates of self-protection and cultural preservation who wish to close the door against the entry of any more. Europe is in the spotlight for the moment, but parallel debates have long been going on across the world — from the United States and Canada to South Africa, Australia, Indonesia, and Japan.

The immediate precipitant of the European debate is the massive outflow from Syria, where the deterioration of the conflict has created an acute state of personal danger for a very large percentage of the population. Syria has become a country to which it is considered against international law to return emigrants. The debate has been about what therefore to do.

There are three different ways in which one can analyze the underlying issues: in terms of the consequences of migrants for the world and national economies, for local and regional cultural identities, and for the national and world political arenas. A good part of the confusion stems from a failure to distinguish these three perspectives.

If one starts with the economic consequences, the principal question is whether taking in migrants is a plus or minus for the receiving country. The answer is that it depends on which country.

We are now familiar with the demographic transition in which the wealthier the country, the more likely it is that families with middle-level incomes will have fewer children. This is basically because reproducing for one's child the same or higher income prospects requires a considerable investment in formal and informal education. This is financially burdensome if one does it for more than one child. In addition, improved health facilities result in longer-lived populations.

The consequence over time of a lowered birthrate and longer lives is that the demographic profile of a country becomes tilted to a higher percentage of older persons and a lengthening of the period in which a child is kept out of the active labor market. It follows that fewer persons in the active work range are supporting an increased number of persons at the older and younger age ranges.

One solution for this is to accept migrants, who can expand the proportion of the active work force and thereby ease the problem of financial support for the older and younger populations of the country. Against this argument is the assertion that the immigrants tap welfare resources and are therefore costly. But the welfare outputs seem to cost far less than the income from the active work inputs plus the additional taxes from working immigrants.

The situation is of course quite different in less wealthy countries, where the major impact of accepting migrants would be precisely to threaten the jobs of a population still willing to agree to do onerous work because of the country's overall demographic profile.

As for the world-economy as a whole, migration merely shifts the location of individuals and probably changes very little. Migrants do however pose a global cost because of the necessity to limit the negative humanitarian consequences of enormous numbers of migrants. Just think of paying for rescuing drowning migrants who have fallen off shaky boats in the Mediterranean.

If one looks at the question from the perspective of cultural identity, the arguments are quite different. All states promote a national identity as a necessary mechanism of ensuring the primacy of allegiance. But of what national identity are we talking? Is it French-ness or Chinese-ness? Or is it Christian-ness or Buddhist-ness? This is precisely the question that differentiates the position of Germany's Chancellor Angela Merkel and Hungary's President Viktor Orban. Merkel asserts that new migrants of whatever ethnic or religious origin can be integrated as German citizens. Orban sees Muslim migrants as invaders that threaten the permanence of Hungary's Christian identity.

The debate extends beyond national boundaries. For Merkel, the migrant’s integration is not only to Germany but to Europe. For Orban, the migrant’s threat is not only to Hungary, the state, but to all of "Christian Europe." But see the comparable debate in France about Muslim garb for women. For some, the question is not relevant if the migrants give their loyalty to France as a citizen. But for defenders of an absolute version of laicité, Muslim garb for women is totally unacceptable, violating the cultural identity of France.

There is no middle path in this kind of cultural debate. It creates an absolute impasse. And precisely because it creates an impasse, this pushes the discussion to the political arena. The ability to prevail in implementing a cultural priority depends on being able to control the political structures. Merkel and Orban, as every other politician, must obtain political support (including of course votes) or they are removed from the decision-making process. In order to maintain themselves in office, they often have to make concessions to strong currents of opinion that they do not like. This may also involve adjustments in economic policy. So, if on one day they lay out a clear line of policy, the next day they may seem to be less firm. The actors have to maneuver in a national, regional, and world political arena.

Where will Europe be ten years from now in terms of feelings about migrants? Where will the world be? It is an open question. Given the chaotic realities of a world in transition to a new historical system, we can only say that it depends on the moment-by-moment changing strengths of the contesting programs for the future. Migrants are one locus of the debate, but the debate is much wider.

- Immanuel Wallerstein, Senior Research Scholar at Yale University, is the author of The Decline of American Power: The U.S. in a Chaotic World (New Press).

Copyright ©2015 Immanuel Wallerstein -- used by permission of Agence Global.