Refugee problems today tend to have one factor in common-the huge numbers of people involved. But whether it is a case of one or of a mass of individuals, each arriving asylum seeker represents a challenge to established principles of state sovereignty. International jurists once wrote of the free movement of persons between nations, unhampered by passport and visa control. Since the late nineteenth century, however, the principle most widely accepted has been that each state retains exclusive control- an absolute discretion- over the admission to its territory of foreign nationals, refugees or not. Although in practice many countries concede that certain individuals may have some claim to enter (e.g., the close family members of local citizens or lawful residents), such claims must rely for their enforcement and implementation upon municipal law, and only rarely does international law have any relevance.
Guy S. Goodwin-Gill,
Entry and Exclusion of Refugees: The Obligations of States and the Protection Function of the Office of the United Nations High Commissioner for Refugees,
Mich. J. Int'l L.
Available at: https://repository.law.umich.edu/mjil/vol3/iss1/13