Abstract: Many poor and oppressed people wish to leave their countries of origin in the third world to come to affluent Western societies. This essay argues that there is little justification for keeping them out. The essay draws on three contemporary approaches to political theory—the Rawlsian, the Nozickean, and the utilitarian—to construct arguments for open borders. The fact that all three theories converge upon the same results on this issue, despite their significant disagreements on oth