Many applicants for social housing were born in Bangladesh. So even after living in the United Kingdom for many decades, they are formally migrants. This raises one of the central questions in calculating migration’s welfare externalities: How do we regulate the welfare state in a world structured by global flows of people and resources? Migration’s social costs in housing shortages and ethnic competition focus on dense city neighborhoods, even where the economic benefits of Bangladeshi migration have been immense. Today, sink estates bought through right-to-buy take-ups of old council rentals (by old Jewish and Irish families and by Bangladeshi migrants) are let out to Lithuanians and Russians, and Roman Catholic school enrollment is rising again. Who has the right to demand welfare support in today’s globalized world? Whose communities should be provided welfare?

Theoretically, this might make us think about a tension between communitarian belonging and sentimental transnationalism. Practically, the most effective integration depended on three strategies to diffuse eligibilitycriteria conflict. First, strong policy planning increased the social housing supply by extracting at least 25 percent of all new private housing development for public amenity (and up to 50 percent where accompanied by state subsidy). Second, transparent allocation systems encouraged people to “choose” properties and see the results of their preference in their place on the allocation queue. Third, eligibility criteria explicitly addressed both social need and the queuing element of waiting for social housing. Such practices focus on the eligibility criteria of migrants to the city. They cannot eliminate social conflict but can enhance a sense of progressive urban change in all sections of the community.

Some cases of migration’s welfare externalities challenge the conventional measurement of its fiscal impacts. Within a static model of the city, including new migrants in the rationing of public goods increases objective welfare costs. But some policy makers, considering a more dynamic model, might argue that excluding new migrants from the rationing of public goods decreases the long-term benefits of migration, as the new migrants’ potential contribution to the city economy is not fully realized. Yet allowing newcomers access to state-financed social inclusion (in schooling, health care, welfare services, and housing) potentially undermines the solidarities of existing city dwellers and may thus have social consequences.

These dilemmas highlight two challenges for policy makers in 21st-century city governments. First, the great movement into cities replicates a standard tradeoff in migration studies. Some scholars believe that there might be a tradeoff between restricting the numbers of migrants allowed into a country and extending rights to new migrants.<sup>3</sup> In other words, it might be easier for policy makers to increase the numbers of international migrants in a country that restricts migrant rights than in a country that immediately grants new migrants full citizenship. Second, the immediate impacts of new migrants may focus on current labor demand (a static model of the city economy), but the longer impact may reflect labor demand beyond a single economic cycle and social trends across several generations (a dynamic model).

How well people sustain international connections also raises analytical and moral challenges for policy makers. In today’s societies, where both mobility and international connection have increased exponentially, migrants may sustain links between locations; “home” may refer both to places where families arrive and to places where families are rooted. As the distinction between permanent and temporary migration potentially blurs as a result, maintaining longer term transnational links takes on more meaning. In the 21st century, we are already seeing countercyclical flows, as Brazilian and Colombian migrants to Madrid and London return to the more dynamic Latin American economies, and policy debates on