In the dissertation I argue that the United States has always been selective in determining where immigrants may come from and under what conditions, including undocumented status, to create a category of persons who are neither slave nor free. First, I show that American legislatures have developed this ability by setting immigration preferences throughout the nation's history to forge mixed settlements between multiple political, economic, and cultural interests with regard to immigration. I then draw preference systems from the Christian tradition-David Hollenbach's priority principles, Gustavo Gutierrez's preferential option for the poor, and Thomas Aquinas' order of charity-to argue that current U.S. immigration preferences are not simply wrong, but backwards. These preference systems, I conclude, offer moral grounds for prioritizing the legalization of undocumented immigrants. They also suggest that meaningful immigration reform requires no less than ending America's dependence on immigrant workers who are neither slave nor free.