international human rights law. As the Committee on Civil and Political Rights clearly states in relation to the International Covenant on Civil and Political Rights: “In general, the rights set forth in the Covenant apply to everyone, irrespective of reciprocity, and irrespective of his or her nationality or statelessness… Thus, the general rule is that each one of the rights of the Covenant must be guaranteed without discrimination between citizens and aliens.”70 This also applies to the International Covenant on Economic, Social and Cultural Rights. However, international human rights law does not prohibit differentiation of treatment altogether. Differentiation will not constitute discrimination if the criteria are reasonable and objective and if the aim is to achieve a purpose that is legitimate under the Covenant.71 Differentiation in treatment will occur between citizens and non-citizens or between different categories of non-citizens, but it must be legitimate under international human rights law. Although the state retains the sovereign right to make distinctions between different categories of non-citizens, this distinction shall not be at variance with the principle of non-discrimination.72 The state has the sovereign right to control its borders, and its immigration policy has traditionally been left to its discretion. However, all persons enjoy inalienable human rights from birth. International human rights instruments have been compiled in recognition of these underlying principles. Non-citizens must be treated within an immigration policy legitimate under international human rights laws. International human rights laws bind states in differentiating non-citizens by immigration status. Today, in mainly industrialized countries, one should not only take account of the distinction between citizens and non-citizens, but also the different categories of non-citizens ranging from permanent residents, who enjoy rights similar to that of citizens, to undocumented aliens at the far end of the spectrum. The establishment of different categories for aliens in itself does not constitute discrimination, but if its 70 General Comment No. 15: The Position of Aliens under the Covenant: 11/04/86, paras.1, 2. General Comment No.18: Non-discrimination: 10/11/89, para. 13. 72 The Human Rights Committee, pursuant to Article 1 of the International Convention on the Elimination of All Forms of Racial Discrimination and the Convention on the Elimination on Against All Forms of Discrimination Against Women, states that the term discrimination as used in the Covenant should be understood to imply any distinction, exclusion, restriction or preference which is based on any ground such as race, colour, sex, language, religion political or other opinion, national or social origin, property, birth or other status, and which has the purpose or effect of nullifying or impairing the recognition, enjoyment or exercise by all persons, on an equal footing, of all rights and freedoms. Id., para. 7. 71 30