Risse, Mathias (2009). "Immigration, Ethics and the Capabilities Approach" United Nations Development Programme, Human Development Reports Research Paper 2009/34 United Nations Development Programme pp. 1-58

Often, immigration debates are conducted under the presumption that immigration policies must be justifiable only to those who already live in the respective country. Alas, reflection on the justifiability of immigration policies to those excluded becomes ever more important in a politically and economically increasingly interconnected world. This study explores two approaches to the normative reflection on immigration at some depth, namely, the idea that restrictive immigration policies are problematic because they are hampering the development of human capabilities, as well as the idea that such policies are problematic because they are at odds with the fact that our planet belongs to humanity collectively. On both of these proposals, less restrictive immigration policies are not merely demanded as one possible way of aiding the poor, but would be required as such. Both of these approaches can be treated within the same framework, the grounds-of-justice framework, which allows us to focus on the idea that states must also be justified to those who do not belong to them. Central to the proposal about immigration that can be made within this approach are ideas of over- and under-use of commonly owned resources and spaces.