CYIL Vol. 4, 2013

ADDRESSING THE RELATIONSHIP BETWEEN STATE IMMUNITY AND JUS COGENS to ongoing controversy in States practise related to this issue, to remove the notion of peremptory norms from the future Convention, it observed that municipal courts had shown “some sympathy” for “the argument increasingly put forward that immunity should be denied in the case of death or personal injury resulting from acts of a State in a violation of human rights norms having the character of jus cogens ”. 27 Some authors describe the failure of the Convention to expressly include the relationship between State immunity and jus cogens as “resulting in regressive development of international law”. 28 Nevertheless, the Convention itself affirms in the Preamble “the rules of customary international law continue to govern matters not regulated by [its] provisions”. Third, the intention of States while signing a treaty should be taken into account. This intent may be found in interpretative declarations and reservations made by States to the Jurisdictional Convention. Several States 29 declared that they understood the Convention “without prejudice to any future international legal development concerning the protection of human rights”; one of them made an express statement 30 to interpret the effect of Article 12 of the Convention (that withholds immunity in situations of personal injuries) in terms of pecuniary compensation for serious human rights violations which are alleged to be attributable to a State and are committed even outside the State of the forum. Finally, it must be underlined that State Parties cannot consider the rules on State immunity embraced in the Convention without due regard to any relevant rules of international law applicable in the relations between them. 31 2. Customary Law International custom, a source of international law qualitatively equal to international treaties, is constituted by a general State practise accepted as law. 32 Such a practise, visible in the States’ national jurisprudence and, secondarily, domestic legislation, will be now examined. 33 As to the U.S. practise in this regard, the restricted approach to State immunity followed by its occasional withholding in cases of serious breaches of international 27 Report of the Working Group on Jurisdictional Immunities of States and Their Property, U.N. Doc. A/CN.4/SER.A/1999/Add.1 (Part 2). 28 See McGregor, L., State Immunity and Jus Cogens. In ICLQ, Vol. 55 (2006), p. 437. 29 Italy, Norway, Sweden and Switzerland. 30 Switzerland. Text of interpretative declarations available at http://treaties.un.org/Pages/ViewDetails. aspx?mtdsg_no=III-13&chapter=3&lang=en [accessed June 15, 2013]. 31 See Article 31 (2) (c) of the Vienna Convention. 32 See Art 38 (1) (b) of the Statute of the International Court of Justice. 33 The relevance of national courts decisions to determining the content of customary law is acknowledged both by theory and international courts. Brownlie, I., Principles of Public International Law (7th ed.), Oxford University Press, 2008, attributes them an indirect evidential power to determine the practice of the State, at p. 23. See also Jennings, R. – Watts, A. (eds.), Oppenheim’s International Law (9th ed.), Longmann, 1992, Vol. 1, pp. 26 and 41. The ICJ itself pronounced in Jurisdictional Immunities Case on the significance of domestic decisions in evidencing States practice and opinio juris. See Jurisdictional Immunities Case , paras. 55, 77.