All high-income countries are facing accelerating migration from poor countries. Although the reason why such migration accelerates has only recently been rigorously established, it is not complicated. Long distance international migration is too costly for very poor people to afford. But as diasporas accumulate in host countries, they make migration easier by providing a network, a place to stay, and finance. (By a diaspora I mean those immigrants who retain strong connections with their country-of-origin).
So diasporas fuel migration and, of course, migration fuels diasporas. As migration accelerates and diasporas grow, social diversity tends to increase. Offsetting this increase is the gradual absorption of migrants into mainstream society. Not only does absorption reduce diversity, as migrants lose their connections to their country-of-origin they no longer ease further migration and so do not contribute to acceleration. So the diaspora stabilizes once absorption matches immigration. Only once the diaspora stabilizes does social diversity stop rising.
Diversity has both beneficial and detrimental effects. It tends to accelerate innovation and increase variety of choice, but it weakens the mutual regard among citizens on which cooperation for public goods, and generosity for transfers, rest. Both the benefits to innovation and the benefits to mutual regard are likely to be subject to decreasing returns and so there is a balance – a happy medium level of diversity. Recent research in development economics suggests that this trade-off with a happy medium as optimal is a very old and robust global phenomenon.
Bringing these two building blocks together, if there is an ideal level of diversity, there is an optimal rate of immigration that is determined by the rate of migrant absorption. In the case of migration from very poor countries to very rich ones, where the economic incentive is enormous, this optimum will be exceeded unless immigration policies prevent it, since in the absence of policy intervention migration will accelerate.
Among the high-income societies, European countries are the ones that have found immigration most problematic. This is partly because their migration policies are less thought through. The societies built on migration – USA, Canada, Australia and New Zealand – have migration in their DNA and so are not embarrassed to debate policy. The Gulf States and Japan have unashamedly banned immigration other than as guest workers and so citizen diversity is unaffected.
In contrast, Europe’s migration policies are badly designed and ill-coordinated because coherent discussion has been taboo. The racist right has set the terms and tone of discussion, in the process driving social science into pro-migration advocacy rather than providing the impartial analysis needed for redesign. But Europe’s distinctive problems over migration also reflect the fact that policy faces greater difficulties. Europe’s cultures do not provide the ready absorption of the societies recently built through migration, so that a given rate of immigration increases diversity more rapidly. Further, Europe is more exposed to increases in diversity, since its governments have achieved more in terms of cooperation and generosity than anywhere else in the world.
The responsibility for breaking the migration taboo and opening informed discussion rests predominantly with the political left. The legitimate right is too exposed to contamination from the illegitimate right to be able to maintain balance. The left will need to acknowledge that migration controls are not an anachronistic reflection of racism, but will become increasingly necessary in all high-income societies: the issue of controls is not existential. Diversity is not an unqualified blessing, and popular concern over the rapidly rising diversity of recent decades might be allayed if the concept of optimal diversity was introduced.
Obviously, the left must maintain its robust opposition to racism, but the suggestion that concern over immigration is intrinsically racist mistakenly condemns a substantial proportion of the indigenous citizenry. The core discussion can then be about the design of controls. The composition of migration is probably more important than any absolute ceilings. Composition is strongly affected by how the rights of members of the diaspora to bring in relatives and prospective spouses are specified. The extrapolation of a right which the indigenous population little uses, to an immigrant population which makes heavy use of it, is ethically complex and does not warrant glib prescriptions.
Ultimately, there will need to be a debate about cultural separatism which distinguishes clearly between culture and race. Continued cultural separatism and rapid immigration may gradually weaken the mutual regard which underpins European welfare systems. This possibility is better discussed than denied.