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Summaries of the Work of the International Law Commission

Unilateral acts of States

See also: Analytical Guide | Texts and Instruments

At its forty-eighth session, in 1996, the International Law Commission, on the basis of the recommendation of a Working Group on the long-term programme of work, identified the topic of “Unilateral acts of States” as appropriate for codification and progressive development. The Working Group noted the relationship between this topic and the more general topic of “Sources of International Law” envisaged as a global topic of codification in the memorandum submitted by the Secretary-General at the first session of the Commission, in 1949.1 The Working Group concluded that the present topic was appropriate for immediate consideration for the following reasons: (1) it is a well delimited topic which has not been studied by any international official body; (2) it has been touched upon in several judgments of the International Court of Justice (ICJ), especially the Nuclear Tests cases,2 but the dicta left room for uncertainties and questions; (3) States have abundant recourse to unilateral acts and their practice can be studied with a view to drawing general legal principles; and (4) the law of treaties provides a point of departure and a scheme of reference for approaching the rules relating to unilateral acts notwithstanding the differences between the two topics. The Working Group prepared a tentative general outline of the topic, including explanatory notes, which contained the following sections: (1) Definition and typology; (2) Legal effects and application; (3) Conditions of validity; and (4) Duration, amendment and termination. The Commission adopted the report of the Working Group.3

The General Assembly, in resolution 51/160 of 16 December 1996, invited the Commission to examine further the topic “Unilateral acts of States” and to indicate its scope and content in the light of the comments and observations made during the debate in the Sixth Committee on the report of the Commission and any written comments that Governments may wish to submit.

At its forty-ninth session, in 1997, the Commission established a Working Group on the topic. The Working Group bore in mind the general outline for the study of unilateral acts of States prepared at the previous session as well as the topical summary of the debate held in the Sixth Committee at the fifty-first session of the General Assembly.4 The Working Group concluded that the Commission’s consideration of the topic, with a view to the codification and progressive development of the applicable legal rules, was advisable and feasible for the following reasons:

“(a) In their conduct in the international sphere, States frequently carry out unilateral acts with the intent to produce legal effects. The significance of such unilateral acts is constantly growing as a result of the rapid political, economic and technological changes taking place in the international community at the present time and, in particular, the great advances in the means for expressing and transmitting the attitudes and conduct of States;

(b) State practice in relation to unilateral legal acts is manifested in many forms and circumstances, has been a subject of study in many legal writings and has been touched upon in some judgments of ICJ and other international courts; there is thus sufficient material for the Commission to analyse and systematize;

(c) In the interest of legal security and to help bring certainty, predictability and stability to international relations and thus strengthen the rule of law, an attempt should be made to clarify the functioning of this kind of act and what the legal consequences are, with a clear statement of the applicable law.”5

The Working Group also considered the scope and content of the topic. As regards the scope of the topic, the Working Group concluded that it should be limited to the unilateral acts of States that are intended to produce “legal” effects, creating, recognizing, safeguarding or modifying rights, obligations or legal situations. As to the content of the topic, the Working Group proposed a revised outline which contained the following sections: (1) Definition of unilateral legal acts of States; (2) Criteria for classifying unilateral legal acts of States; (3) Analysis of the forms, the characteristics and the effects of the most frequent unilateral acts in State practice; (4) General rules applicable to unilateral legal acts; and (5) Rules applicable to specific categories of unilateral legal acts of States.6

The Commission endorsed the report of the Working Group; appointed Victor Rodrígues Cedeño as Special Rapporteur for the topic; requested the Special Rapporteur to submit at its next session his first report which would include a general outline of the topic containing a brief description of State practice, a survey of relevant judicial decisions and literature, and a detailed scheme for the substantive development of the topic; and invited Governments to express their views on the topic, in the Sixth Committee and separately in writing, and to provide information relevant for the study of the topic.7

The General Assembly, in resolution 52/156 of 15 December 1997, endorsed the Commission’s decision to include in its agenda the topic “Unilateral acts of States”.

At its fiftieth session, in 1998, the Commission had before it the first report8 of the Special Rapporteur the aim of which was to identify, by considering the various acts and forms of conduct of States, the constituent elements of a definition of a unilateral act of a State. The report dealt with the existence of unilateral acts of States, the criteria for identifying strictly unilateral acts of States and the legal basis for the binding character of these acts. After considering this report, the Commission decided to establish the Working Group on Unilateral acts of States.

The Working Group considered the scope of the topic, the form of work on the topic and the future work of the Special Rapporteur. As regards the scope of the topic, the Working Group endorsed the approach taken by the Special Rapporteur in his report, which was consistent with the outline adopted by the Commission at its forty-ninth session, and which limited the topic to unilateral acts of States issued for the purpose of producing international legal effects. This excluded from the topic’s scope acts of States which do not produce legal effects, unilateral acts of the State which are linked to a specific legal regime and acts of other subjects of international law, such as acts of international organizations. As to the form of the work, the Working Group believed that the elaboration of draft articles with commentaries was the most appropriate way to proceed, without prejudging the final legal status of the draft articles which could be in the form of a convention, guidelines, a restatement or any other outcome. As regards future work, the Working Group recommended that the Special Rapportuer be requested to prepare a second report including: (1) draft articles on the definition of unilateral acts and the scope of the draft articles, based on the report of the Working Group concerning these issues; and (2) a further examination of the elaboration of unilateral acts and the conditions for their validity. The Commission endorsed the report of the Working Group.9

At its fifty-first session, in 1999, the Commission had before it the second report10 of the Special Rapporteur which addressed certain questions raised by Governments in the Sixth Committee in 1998 in commenting on the report of the Commission on this topic, namely: the relationship between the unilateral acts that are the subject of this study and the international responsibility of States; unilateral acts and estoppel; and unilateral acts relating to international organizations, particularly State acts addressed to such organizations. In addition, the Special Rapporteur proposed the following draft articles: 1 (the scope of the draft articles), 2 (the definition of unilateral acts of States), 3 (the capacity of States to formulate unilateral acts), 4 (the representatives of a State for the purpose of formulating unilateral acts), 5 (subsequent confirmation of a unilateral act formulated without authorization), 6 (the validity of unilateral acts in terms of the expression of consent) and 7 (the invalidity of unilateral acts). After considering this report, the Commission decided to reconvene the Working Group on Unilateral Acts of States.

The Working Group considered the following issues concerning the way in which the Commission’s work on the topic should proceed: (a) the basic elements of a workable definition of unilateral acts as a starting point for further work on the topic as well as for gathering the relevant State practice; (b) the general guidelines for gathering the relevant State practice, including a questionnaire to be sent to Governments; and (c) the direction that the work of the Special Rapporteur should take in the future. As regards the definition, the Working Group agreed that the following concept could be taken as the basic focus for the Commission’s study of the topic: “A unilateral statement by a State by which such State intends to produce legal effects in its relations to one or more States or international organizations and which is notified or otherwise made known to the State or organization concerned.”11 As to relevant State practice, the Working Group established guidelines for a questionnaire to be sent to States requesting materials and inquiring about their practice with respect to unilateral acts as well as their position on certain aspects of the Commission’s study of the topic.12 With respect to future work, the Working Group recommended that the Special Rapporteur: continue, taking into account the relevant State practice, formulating new draft articles; consider, in the light of the comments made in the Commission, reformulating the draft articles contained in his second report; and examine the interpretation, effects and revocability of unilateral acts. The Commission adopted the report of the Working Group as amended by the Commission.13

At its fifty-second session, in 2000, the Commission had before it the third report14 of the Special Rapporteur, as well as the replies received from Governments to the questionnaire circulated in 1999.15 In his third report, the Special Rapporteur examined some preliminary issues such as the relevance of the topic, the relationship between the draft articles on unilateral acts and the 1969 Vienna Convention on the Law of Treaties, as well as the question of estoppel and unilateral acts. The Special Rapporteur also proposed a reformulation of the draft articles contained in his second report, including: the deletion of the previous draft article 1 (Scope of the present draft articles); a new draft article 1 [2]16 (Definition of unilateral acts); a new draft article 2 [3] (Capacity of States to formulate unilateral acts); a new draft article 3 [4] (Persons authorized to formulate unilateral acts on behalf of the State); a new draft article 4 [5] (Subsequent confirmation of an act formulated by a person not authorized for that purpose); the deletion of previous draft article 6 (Expression of consent); and a new draft article 5 [7] (Invalidity of unilateral acts). The Special Rapporteur concluded that it was not necessary to include a draft article based on article 3 of the Vienna Convention on the Law of Treaties, which addresses the legal force of international agreements not within the scope of the Convention and the provisions of international law which apply to them, since the reference to unilateral acts in the present draft articles is broad enough to cover all unilateral expressions of will formulated by a State. In connection with the proposed deletion of article 6, the Special Rapporteur also examined the question of silence and the formulation of unilateral acts. After considering this report, the Commission referred draft articles 1 to 4 to the Drafting Committee and draft article 5 to the Working Group for further consideration and study.

The Working Group did not have sufficient time to consider draft article 5 or to draw any final conclusions concerning the topic. Nonetheless, the Working Group noted that there was a strong measure of support for the following points concerning (a) the scope of the topic; (b) the structure of the draft articles; and (c) future work on the topic:

“(a) The kind of unilateral acts with which the topic should be concerned are non-dependent acts in the sense that the legal effects they produce are not pre-determined by conventional or customary law but are established as to their nature and extent, by the will of the author State.

(b) The draft articles could be structured around a distinction between general rules which may be applicable to all unilateral acts and specific rules applicable to individual categories of unilateral acts.

(c) The Special Rapporteur could initiate the study of specific categories of unilateral acts by concentrating first on those acts which create obligations for the author State (promises), without prejudice to recognizing the existence of other categories of unilateral acts such as protest, waiver and recognition, which could be addressed at a later stage.”17

The Working Group also recommended that further work on the topic should pay particular attention to State practice and that efforts to gather relevant State practice should continue. Although it did not have time to consider the report of the Working Group, the Commission agreed that it would be useful to seek the views of Governments on points (a), (b) and (c) above.

At its fifty-third session, in 2001, the Commission had before it the fourth report18 of the Special Rapporteur which dealt with the classification of unilateral acts as a prerequisite to the formulation of common rules for various categories of unilateral acts and the extent to which the rules of interpretation contained in the Vienna Convention on the Law of Treaties were applicable mutatis mutandis to unilateral acts. The Special Rapporteur proposed a classification of unilateral acts based on the legal effects criterion. The Special Rapporteur also proposed draft articles (a) (General rule of interpretation) and (b) (Supplementary means of interpretation) based on the provisions concerning the interpretation of treaties contained in articles 31 and 32 of the Vienna Convention. These provisions were adapted to reflect the particular nature of unilateral acts by providing for a subjective rather than an objective interpretation of a unilateral act as well as a restrictive interpretation of the self-imposed restriction of sovereignty implied by the act. After considering the report, the Commission established a Working Group, chaired by the Special Rapporteur. At the recommendation of the Working Group, the Commission requested the Secretariat to circulate a questionnaire to Governments inviting them to provide further information regarding their practice of formulating and interpreting unilateral acts.19

At its fifty-fourth session, in 2002, the Commission had before it the fifth report20 of the Special Rapporteur as well as the replies received from Governments21 to the questionnaire circulated in 2001. In his fifth report, the Special Rapporteur dealt with the following: (a) the progress made on the topic; (b) the definition of unilateral acts, conditions of validity and causes of invalidity, rules of interpretation and classification of unilateral acts; (c) the possible elaboration of common rules applicable to all unilateral acts; (d) entry into force and determination of the moment at which the unilateral act begins to produce its legal effects; and (e) the structure of the draft articles as well as the future plan of work. The Special Rapporteur proposed the following draft articles: revised 5 (a) to (h) (invalidity of a unilateral act as a result of error, fraud, corruption of the State representative, coercion of the person formulating the act, coercion by the threat or use of force, a contrary peremptory norm of international law (jus cogens), a contrary Security Council decision, or a contrary fundamental norm of domestic law); (a) and (b) (general rule and supplementary means of interpretation); 7 (acta sunt servanda); 8 (non-retroactivity); and 9 (territorial application). After considering the report, the Commission established an open-ended informal consultation, chaired by the Special Rapporteur, on unilateral acts of States.22

At its fifty-fifth session, in 2003, the Commission had before it the sixth report23 of the Special Rapporteur which focused on the unilateral act of recognition. After considering the report, the Commission established a Working Group, chaired by Alain Pellet, which dealt with the scope of the topic and the method of work. The Working Group made the following recommendations: (1) for the purposes of the present study, a unilateral act of a State is a statement expressing the will or consent by which that State purports to create obligations or other legal effects under international law; (2) the study will also deal with the conduct of States which may create obligations or other legal effects under international law similar to those of unilateral acts; (3) the study will propose draft articles accompanied by commentaries with respect to unilateral acts and, if appropriate, guidelines or recommendations with respect to other conduct; (4) the Special Rapporteur’s report to be submitted at the Commission’s next session will present State practice concerning unilateral acts and will include information originating with the author of the act or conduct as well as the reactions of other States or actors concerned; (5) the empirical information should enable the identification of rules applicable to unilateral acts stricto sensu, with a view to preparing draft articles accompanied by commentaries, as well as rules which might be applicable to State conduct producing similar effects; (6) the orderly classification of State practice should address the reasons for the unilateral act or conduct of the State, the criteria for the validity of the express or implied commitment of the State and the circumstances in which the unilateral commitment can be modified or withdrawn; and (7) the legal rules which may be deduced from the material submitted will be dealt with in later reports for preparing specific draft articles or recommendations. The Commission adopted the recommendations of the Working Group.24

At its fifty-sixth session, in 2004, the Commission had before it the seventh report25 of the Special Rapporteur. Following the recommendations made by the Commission in 2003 (particularly recommendation No. 4), the report related to the practice of States in respect of unilateral acts and took account of the need to identify the relevant rules for codification and progressive development. It covered acts and declarations producing legal effects. In order to determine the criteria for the classification of acts and declarations, the Special Rapporteur used three generally established categories: acts by which a State assumes obligations (promise and recognition); acts by which a State waives a right (waiver); and acts by which a State reaffirms a right or a claim (protest). After considering the report, the Commission re-established the Working Group, chaired by Alain Pellet. The Working Group agreed to retain a sample of unilateral acts sufficiently documented to allow for an analysis in depth, and established the following grid which would permit to use uniform analytical tools26:

At its fifty-seventh session, in 2005, the Commission considered the eighth report27 of the Special Rapporteur which provided 11 examples or types of unilateral acts of various kinds, followed by a set of conclusions drawn from the cases discussed. After considering the report, the Commission again reconstituted the Working Group, chaired by Alain Pellet.28 The Working Group undertook an analysis of the specific cases in accordance with the grid established at the fifty-sixth session of the Commission (2004) and the conclusions that could be drawn from that analysis. The Commission subsequently requested the Working Group to consider several points raised in the general debate on which there was general agreement that might form the basis of preliminary conclusions or proposals on the topic that the Commission could consider at its fifty-eighth session. In response, the Working Group acknowledged that, while it could be stated in principle that the unilateral conduct of States could produce legal effects, whatever form that unilateral conduct might take, it would attempt to establish some preliminary conclusions in relation to unilateral acts stricto sensu. The Working Group also briefly considered questions relating to the variety of unilateral acts and their effects, the importance of circumstances in assessing their nature and effects, their relationship to other obligations of their authors under international law and the conditions of their revision and revocability.29

The work of the Commission on the topic as described above has been proceeding in accordance with the successive resolutions adopted by the General Assembly30 under the item relating to the report of the International Law Commission. The General Assembly has drawn the attention of Governments to the importance for the International Law Commission of having their views on various aspects of the topic and invited Governments to provide relevant information as requested by the Commission.

1 Document A/CN.4/1 (United Nations publication, Sales No. 48.V.1) reissued under the symbol A/CN.4/1/Rev.1 (United Nations publication, Sales No. 48.V.1(1)).

2 Nuclear Tests (Australia v. France, New Zealand v. France), Judgment, I.C.J. Reports 1974, pp. 253 and 457.

3 See Yearbook of the International Law Commission, 1996, vol. II (Part Two), para. 245 and annex II, addendum 3.

4 Document A/CN.4/479, section E.6. (see Analytical Guide)

5 See Yearbook of the International Law Commission, 1997, vol. II (Part Two), para. 196.

6 See Yearbook of the International Law Commission, 1997, vol. II (Part Two), paras. 197–210.

7 See Yearbook of the International Law Commission, 1997, vol. II (Part Two), paras. 194, 212 and 213.

8 Document A/CN.4/486. (see Analytical Guide)

9 See Yearbook of the International Law Commission, 1998, vol. II (Part Two), paras. 194–201.

10 Document A/CN.4/500 and Add.1.

11 See Yearbook of the International Law Commission, 1999, vol. II (Part Two), para. 589.

12 For replies from Governments to the questionnaire, see document A/CN.4/511 (see Analytical Guide). The document contains the text of the replies received as at 6 July 2000.

13 See Yearbook of the International Law Commission, 1999, vol. II (Part Two), paras. 577–597.

14 Document A/CN.4/505. (see Analytical Guide)

15 Document A/CN.4/511. (see Analytical Guide)

16 The numbers in square brackets correspond to the numbers of the draft articles proposed by the Special Rapporteur in his second report.

17 See Official Records of the General Assembly, Fifty-fifth session, Supplement No. 10 (A/55/10), para. 621. (see Analytical Guide)

18 Document A/CN.4/519. (see Analytical Guide)

19 For the replies from Governments, see document A/CN.4/524 (see Analytical Guide). The document contains the text of the replies received as at 14 March 2002.

20 Document A/CN.4/525 and Add.1, Corr.1, Corr.2 and Add.2. (see Analytical Guide)

21 Document A/CN.4/524. (see Analytical Guide)

22 See Official Records of the General Assembly, Fifty-seventh Session, Supplement No. 10 (A/57/10), para. 295. (see Analytical Guide)

23 Document A/CN.4/534. (see Analytical Guide)

24 See Official Records of the General Assembly, Fifty-eighth Session, Supplement No. 10 (A/58/10), paras. 17, 244, 245, 303, 306 and 308. (see Analytical Guide)

25 Document A/CN.4/542 and Corr.1, Corr.2 and 3. (see Analytical Guide)

26 See Official Records of the General Assembly, Fifty-ninth Session, Supplement No. 10 (A/59/10), para. 247. (see Analytical Guide)

27 Document A/CN.4/557. (see Analytical Guide)

28 See Official Records of the General Assembly, Sixtieth Session, Supplement No. 10 (A/60/10), para. 327. (see Analytical Guide)

29 See Official Records of the General Assembly, Sixtieth Session, Supplement No. 10 (A/60/10), paras. 328–331. (see Analytical Guide)

30 General Assembly resolutions 53/102 of 8 December 1998, 54/111 of 9 December 1999, 55/152 of 12 December 2000, 56/82 of 12 December 2001, 57/21 of 19 November 2002, 58/77 of 9 December 2003, and 59/41 of 2 December 2004. (see Analytical Guide)