International Law Commission International Law Commission

Last update: July 15, 2015

Analytical Guide to the Work of the International Law Commission

Question of defining aggression

See also: Summary | Texts and Instruments


Studies undertaken by the Secretariat and Reports of the Secretary-General


Reports of the Working Group or Sub-Committee


Reports of the Special Rapporteur

  • Report entitled, "The Possibility and Desirability of a Definition of Aggression" prepared by the Special Rapporteur as an annex to his report on the Draft Code of Offences against the Peace and Security of Mankind. After a survey of previous attempts to define aggression, the Special Rapporteur stated that "whenever governments are called upon to decide on the existence or non-existence of 'aggression under international law', they base their judgment on criteria derived from the 'natural', so to speak, notion of aggression... and not on legal constructions. He came to the conclusion that this "natural notion" of aggression is a "concept per se", which "is not susceptible of definition". "A 'legal' definition of aggression would be an artificial construction", which could not be comprehensive enough to comprise all imaginable cases of aggression, since the methods of aggression are in a constant process of evolution.
    • Second report of the Special Rapporteur on the Draft Code of Offences against the Peace and Security of Mankind, Mr. J. Spiropoulos (3rd session of the ILC (1951))

Reports of the Drafting Committee


Comments by Governments



  • 3rd session of the International Law Commission (1951)
    • Memorandum presented by Mr. Gilberto Amado
  • Proposal by Mr. M.J.M. Yepes
  • Memorandum presented by Mr. Ricardo Alfaro
  • Proposal by Mr. Roberto Córdova
  • Proposal by Mr. Shushi Hsu
  • Proposal by Mr. M.J.M. Yepes
  • Definition of aggresson — Text tentatively adopted by the Commission at its 95th meeting, 4 June 1951 — incorporated in footnote 1 of A/CN.4/SR.96
  • Memorandum presented by Mr. Georges Scelle

Reports of the International Law Commission

  • Report of the International Law Commission on the work of its third session, 16 May to 27 July 1951
    • The Commission took as a basis for consideration the text submitted by Mr. Alfaro as it was the broadest definition before the Commission. Although the definition was amended and refined following discussion, some members considered it still to be unsatisfactory as it did not comprehend all conceivable acts of aggression and that it might prove to be dangerously restrictive of the necessary freedom of action of the organs of the United Nations, if they were called upon in the future to apply the definition to specific cases. The definition was rejected by 7 votes to 3. A proposal not to abandon attempts at defining aggression was likewise defeated in a vote. The Commission did, however, decide to continue discussing the topic within the context of the preparation of the Draft Code of Offences against the Peace and Security of Mankind, and therefore included among the offences defined in the draft code any act of aggression and any threat of aggression.
    • Discussion in plenary: 92nd, 93rd, 94th, 95th and 96th meetings (30 May to 5 June 1951), 108th and 109th meetings (21 to 22 June 1951), 127th, 128th and 129th meetings (18 to 20 July), and 133rd meeting (26 July 1951)

General Assembly Action


Final Outcome

International Law Commission (3rd session, 1951)

General Assembly (6th session, 1951)

  • Resolution 599 (VI) of 31 January 1952
    • Concluded that it was both "possible and desirable, with a view to ensuring international peace and security and to developing international criminal law, to define aggression by reference to the elements which constitute it".1

1 See the summary for this topic for a discussion of subsequent activities under this rubric.