Immigration

Catholic teaching on immigration is summarized in the Compendium of Social Doctrine of the Church in the section on Immigration and Work:


 * Immigration can be a resource for development rather than an obstacle to it. In the modern world, where there are still grave inequalities between rich countries and poor countries, and where advances in communications quickly reduce distances, the immigration of people looking for a better life is on the increase. These people come from less privileged areas of the earth and their arrival in developed countries is often perceived as a threat to the high levels of well-being achieved thanks to decades of economic growth. In most cases, however, immigrants fill a labour need which would otherwise remain unfilled in sectors and territories where the local workforce is insufficient or unwilling to engage in the work in question.


 * Institutions in host countries must keep careful watch to prevent the spread of the temptation to exploit foreign labourers, denying them the same rights enjoyed by nationals, rights that are to be guaranteed to all without discrimination. Regulating immigration according to criteria of equity and balance is one of the indispensable conditions for ensuring that immigrants are integrated into society with the guarantees required by recognition of their human dignity. Immigrants are to be received as persons and helped, together with their families, to become a part of societal life. In this context, the right of reuniting families should be respected and promoted. At the same time, conditions that foster increased work opportunities in people's place of origin are to be promoted as much as possible.


 * (emphases original)

There are large literatures on immigration in economics, political science, law, and sociology.