In This Article Expand or collapse the "in this article" section Aliens

  • Introduction
  • General Overviews
  • National and Minimum Standards
  • Expulsion of Aliens
  • Diplomatic Protection
  • Recent International Jurisprudence
  • Calvo Clause
  • Migration and Human Rights
  • Refugees
  • Displaced People
  • Asylees
  • Migrant Workers
  • Undocumented Migrants
  • Jurisprudence of the European Court of Human Rights
  • Inter-American Court of Human Rights

International Law Aliens
Loretta Ortiz
  • LAST REVIEWED: 24 July 2013
  • LAST MODIFIED: 24 July 2013
  • DOI: 10.1093/obo/9780199796953-0047


General international law obliges states to treat aliens in a certain way (alien defined as “non-national”). The standards of general international law governing the treatment of aliens are part of what has been called alien law, which only encompasses the duties of states toward the aliens who are nationals of another state. International alien law can be divided into large areas: admission of aliens, foreigners’ situations in the country, and their expulsion. With regard to the admission of aliens, general international law establishes that a state cannot arbitrarily close its borders, although states may subject entry to their territory to the fulfillment of certain conditions, denying access to certain foreigners or groups of foreigners. Aliens have the rights of recognition of their legal capacity, respect for acquired rights, the right to liberty, the right to access to justice, and protection from criminal attacks, requiring states to punish offenses against the life, liberty, property, and honor of aliens. States fulfill this duty if they protect aliens in the same way as they do their nationals, along with providing the right to consular notification and access in the case of deprivation of liberty. It is noted that the international alien law standards do not impose upon states the duty to authorize work or the exercise of a profession by aliens. Nevertheless, in treaties that create free-trade areas or customs unions, more favorable treatment has been legislated for the foreign nationals or residents of the states parties, in light of those regulations that authorize the exercise of an activity, profession, or job, as in the case of the European Union. Concerning the expulsion of foreigners, the motives supported by international practice can be reduced to the following: putting the security and order of the state of residence in danger; offense inferred to the state of residence; threat or offense to other states; crimes committed within the country as well as abroad; economic damages to the state of residence; and residence in the country without authorization.

General Overviews

The bases of international law are found in immigration issues in Vitoria 1974, and are of special relevance for this topic: Relectio de Potestate Civili, Relectio de Indis, and Relectio de Temperantia. Based on the law of natural society and communication, Vitoria 1974 defines the establishment of the right of foreigners to emigrate with the only limitation being not causing any damage to natives. In the management of what we now know as international law, the right to emigrate was recognized, and in the countries that they emigrated to, foreigners enjoyed all rights, with the only limitation being not doing harm to natives. When referring to this law, Leclercq 1965 says that the right to emigrate addresses the right to settle in another country and the right of the emigrant to become a citizen in the country in which he or she settles. Each of these rights is limited by the rights acquired previously and by the rights of other humans. When referring to the issue of the right to enter a state, O’Connell 1970, a work on international public law, mentions that first Christian Wolff and then Emer de Vattel introduced the idea of the state’s authority to control the entry of foreigners. O’Connell’s work specifies, however, that said internationalists only justified it for security reasons, and therefore the arbitrary exercise of the authority to refuse entry of foreigners was prohibited. Brierly 1963, Brownlie 2008, and Verdross 1931 establish that international law imposes few limits regarding the authority of states to regulate the entry of foreigners into their territory; said subjects determine the conditions of entry, stay, and residence of foreigners. The right to exit a country is regulated, but not the right to enter the territory of another state of which one is not a national, and that creates an absolute discretion for the recipient state to determine the entry requirements of foreigners. On the other side, Cançado Trindade, et al. 1996 locates in international law the prohibition of collective expulsion of aliens, and individual expulsion when the removal of those who legally reside there is arbitrary. In addition, if the immigrant is rejected at the border or remains in the state’s territory illegally, he or she may not be returned to the country in which his or her life or liberty is in danger.

  • Brierly, J. L. The Law of Nations: An Introduction to the International Law of Peace. 6th ed. Oxford: Clarendon, 1963.

    Work on international law that approaches the subject referred to in Part 7, “Limitation upon a State’s Treatment of Aliens” (see pp. 276–304).

  • Brownlie, Ian. Principles of Public International Law. 7th ed. Oxford and New York: Oxford University Press, 2008.

    Work in which the subject of aliens in international law is approached in Part 9, pp. 521–555.

  • Cançado Trindade, Antonio, Gérard Peytrignet, and Jaime Ruiz de Santiago. As três vertentes da proteção internacional dos direitos da pessoa humana: direitos humanos, direito humanitário, direito dos refugiados. San José, Costa Rica, and Brasilia, Brazil: Inter-American Institute of Human Rights, International Committee of the Red Cross, and the Office of the United Nations High Commissioner for Refugees, 1996.

    This work synthesizes the international standards applicable to aliens in the fields of human rights, humanitarian law, and refugee law (see pp. 52–117).

  • Leclercq, Jacques. El derecho y la sociedad: sus fundamentos. Barcelona: Herder, 1965.

    Classic work of legal sociology that refers to the issue of the right and obligations of aliens in society (see p. 244).

  • O’Connell, D. P. International Law. Vol. 2. New York: Oceana, 1970.

    Work of public international law in two volumes, which analyzes the subject of aliens in chapter 22, “Personal Jurisdiction: Aliens” (see pp. 751–815).

  • Verdross, Voirè A. “Les règles internationales concernat le traitement des étrangers.” Hague Academy Collected Courses Online 37 (1931): 323–412.

    In this work, Verdross analyzes the treatment that the foreigners must receive in accordance with international law standards and the rights that constitute the law’s minimum standard. Available online by subscription.

  • Vitoria, Francisco de. Reelecciones del estado, de los Indios y del derecho de guerra. Mexico City: Porrúa, 1974.

    Vitoria became known as one of the founders of public international law in this work analyzing the rights of the Spaniards who emigrated to New Spain (see pp. 60–66).

back to top

Users without a subscription are not able to see the full content on this page. Please subscribe or login.

How to Subscribe

Oxford Bibliographies Online is available by subscription and perpetual access to institutions. For more information or to contact an Oxford Sales Representative click here.