Why do governments form institutions devoted to emigrants and their descendants in the diaspora? Such institutions have become a regular feature of political life in many parts of the world: Over half all United Nations Member States now have one. Diaspora institutions merit research because they connect new developments in the global governance of migration with new patterns of national and transnational sovereignty and citizenship, and new ways of constructing individual identity in relation to new collectivities. But these institutions are generally overlooked. Migration policy is still understood as immigration policy, and research on diaspora institutions has been fragmented, casestudy dominated, and largely descriptive. In this articl...