Liberation theology explores the relationship between Christian theology (usually Roman Catholic) and political activism, particularly in areas of social justice, poverty, and human rights. The main methodological innovation of liberation theology is to do theology from the viewpoint of the economically poor and oppressed of the human community.
Sounds like the policy paper of the UCSSB on illegal immigration and the stance Cardinal Roger Mahoney and his position on illegal immigration.(Religious Marxism)
I don't quite follow how concern for the poor translates into immigration policy myself. Concern for the poor raises a host of complex issues when it comes to public policy, and at some point, such complexity goes way beyond theology as to ways and means. It requires other expertise that most theologians don't possess.