International Law Commission

The International Law Commission was created in 1947 by the United Nations General Assembly Resolution 174 as a means of fulfilling the General Assembly’s objective, stated in Article 13, paragraph 1.a, of the UN Charter, of “encouraging the progressive development of international law and its codification”. Through, respectively, the preparation of draft conventions on matters that do not possess regulation in international law and the more accurate formulation and systematization of rules of international law in areas where there is significant State practice, precedent and doctrine, the Commission seeks to attain its main objects – that of developing international law and that of codifying it.

The main objective of the work of the ILC is to prepare a draft convention, however two other possibilities are contemplated by the Statute: the simple publication of its report or a resolution of the General Assembly taking note of or adopting the report (ILC Statute, Article 23, paragraph 1). The Commission has played a leading role in the crystallization of emerging customary norms of international law. Its Draft Articles on the Responsibility of States for Internationally Wrongful Acts, for instance, albeit consisting of a soft law instrument, have been universally acknowledged and resorted to as a persuasive authority. Also worth pointing out would be what later became the Vienna Convention on Diplomatic Relation, the Vienna Convention on Consular Relations and the Vienna Convention on the Law of Treaties – which, following very closely the texts proposed by the ILC, are almost unanimously considered as having consolidated the pre-existing customary rules on their respective subject matters.

The ILC is composed of 34 members, which “shall be persons of recognized competence in international law” (ILC Statute, Art. 2, paragraph 1). Candidates are nominated by the Governments of Member States and are elected by the UN General Assembly (ILC Statute, Art. 3). Similarly to the judges of the International Court of Justice, the members of the Commission sit in their individual capacity, not representing the interests of their respective governments. Nonetheless, two nationals of the same State cannot be members of the ILC at the same time.

This year, we invite UFRGSMUN’s participants to discuss two important topics currently under the Commission’s consideration: formation and evidence of customary international law and the obligation to extradite or prosecute.


TOPIC A: Formation and evidence of customary international law

It is widely accepted that custom, alongside treaties and general principles of law, is one of the main sources of public international law, as enumerated in Article 38 (1) of the Statute of the International Court of Justice. Nonetheless, international custom is often seen as a problematic means of law-making, mainly due to the grey area involving its character, consistency and acceptance. For that reason, the international community is concerned with establishing a coherent theoretical basis for the formation and evidence of customary international law.

Article 38 (1) (b) defines custom “as evidence of a general practice accepted as law”. This definition leads to the widely accepted two-element theory, according to which international custom is composed of two main elements: on the one hand, State practice, and, on the other hand, opinio juris sive necessitatis. The first can be described as an objective element consisting of any act, articulation or other behavior of a State, and the second, as the notion, by the State, that such practice is required by, or consistent with prevailing international law (ILC 1950, 26). This last element, particularly, although often considered in a superficial manner, as presumed from the existence of practice, is essential to distinguish international custom from mere comity, as the International Court of Justice has recognized in a number of important cases (Brownlie 2008). Setting aside the mists surrounding international custom has also been the main task of the International Law Commission itself, in its work of codification of international norms.

However, the problem still revolves around the practical aspects of the identification of such rules, especially when it comes to the subjective element of opinio juris and the diversity of legal cultures involved. Acknowledging the necessity of a common understanding on the matter, the International Law Commission has included the present topic in its programme of work, seeking to enlighten and to further discuss the many questions related to the formation and identification of customary international law. The focus of the debate shall be, rather than to codify rules, to produce authoritative guidance for those called upon to identify customary international law. The discussions will necessarily cover some central questions, inter alia, the relevant State practice, the relations with soft law and with the law of treaties, the criteria for the identification of both practice and opinio juris, the role of international tribunals, among many others.

The final result of the debates may take one of a number of forms, such as a set of conclusions or guiding principles to be submitted to the United Nations General Assembly, in an effort to further clarify an issue so fundamental to the study and application of international law.


TOPIC B: Obligation to extradite or prosecute (aut dedere aut judicare)

There is, today, a growing concern among the international community about ending impunity for international crimes and grave human rights violations. To that end, efforts have been made to establish appropriate fora for the prosecution and trial of alleged criminals. In this context, the debate over the obligation to extradite or prosecute, also known by the Latin expression aut dedere aut judicare, becomes fundamental, since it aims at “securing international cooperation in the suppression of certain kinds of criminal conduct” (Bassiouni 1995, 3).

The obligation aut dedere aut judicare can be described as an alternative obligation concerning the treatment, by a State, of an alleged offender, according to which a State holding a person accused of certain crimes has an obligation to either prosecute such person or extradite him or her to another country willing to do so. This obligation is included in a number of international treaties, such as the 1984 UN Convention Against Torture and Other Inhuman or Degrading Treatment or Punishment, the 1970 Hague Convention for the Suppression of Unlawful Seizure of Aircraft, along with other conventions relating to terrorism. Furthermore, part of the doctrine affirms that the obligation is also of a customary nature (ILC 2006). Such claim was made by the Kingdom of Belgium, in its Application in the Questions Relating to the Obligation to Prosecute or Extradite (Belgium v. Senegal) case – which concerned Belgium’s requests for the extradition by Senegal of former Chadian president Hissène Habré, accused of torture and other crimes against humanity.

Nonetheless, there are still many doubts surrounding this rule, since many of its main aspects remain unsettled: its possible customary nature, the hierarchy between the two alternatives contained in the formula, the effects on it of the creation of international criminal courts, the crimes comprised in its definition, the difficulties concerning prosecution and extradition processes, among many others that may arise during the debates. When discussing this topic, the Commission shall not only account for the aforementioned issues, but also relate them with core principles of international law, such as State sovereignty, the protection of human rights, which include the right to a fair trial, and the international suppression of certain crimes. The ILC Members must analyze the international practice regarding this issue, looking for evidence of it in treaties, judicial decisions, UNGA and UNSC resolutions, among others.

The result of the Commission’s efforts, which may take the form of a final formulation of the obligation to extradite or prosecute, a set of principles concerning the matter or a report on its conclusions to be submitted to the United Nations General Assembly, will most certainly be one step further in the development of international criminal law.



Bassiouni, M. Cherif; WISE, E.M. Aut Dedere Aut Judicare: The Duty to Extradite or Prosecute in International Law. Dortrecht/Boston/London: Martinus Nijhoff Publishers, 1995.
Brownlie, Ian. Principles of Public International Law. Oxford: Oxford University Press, 2008.
ICJ. Questions relating to the obligation to prosecute or extradite (Belgium v. Senegal) (Applications instituting proceedings), 2009. Available at: Accessed on 9 March 2013.
ILC. Formation and evidence of customary international law – Note by Michael Wood, Special Rapporteur (30 May 2012) UN Doc A/CN.4/653.
ILC. Fourth­ report on the obligation to extradite or prosecute (“aut dedere aut judicare”) by Mr. Zdzislaw Galicki, Special Rapporteur (31 May 2011) UN Doc A /CN.4/648.
ILC. Preliminary report on the obligation to extradite or prosecute (“aut dedere aut judicare”) by Mr. Zdzislaw Galicki, Special Rapporteur (7 June 2006) UN Doc A/CN.4/571.
ILC. Annex A – Formation and evidence of customary international law (Mr. Michael Wood). Report on the work of its sixty-third session (26 April to 3 June and 4 July to 12 August 2011) UN Doc A/66/10.
ILC. Second  report on the obligation to extradite or prosecute (“aut dedere aut judicare”) by Mr. Zdzislaw Galicki, Special Rapporteur (11 June 2007) UN Doc A /CN.4/585.
ILC. Third report on the obligation to extradite or prosecute (“aut dedere aut judicare”) by Mr. Zdzislaw Galicki, Special Rapporteur (10 June 2008) UN Doc A /CN.4/603.
ILC. Article 24 of the Statute of the International Law Commission – Working Paper by Manley O. Hudson (1950) UN Doc A/CN.4/16 and Add.1.
Villiger, Mark Eugene. Customary Internation Law and Treaties: a Manual on the Theory and Practice of the Interrelation of Sources. The Hague/London/Boston: Kluwer Law International, 1997.