Binding force and interpretative value
  1. The degree to which the preamble is binding depends on the facts at stake. While some authors maintain that the preamble has no binding force;[6] others are less categorical, basing themselves in particular on the supplemental character of preambular provisions which can fill gaps that might exist elsewhere in a treaty.[7] However, it seems to be generally recognized that the preamble of an instrument can never take precedence over an operative provision with which it would be incompatible.[8]
  1. In the development of ILO standards, the issue of whether a preamble has binding effect has been raised frequently. The Legal Adviser has consistently recalled that the preamble is non-binding in nature and that its primary function is to set out the context of the instrument.
  1. In contrast, the interpretative value of the preamble of an international convention is beyond question. Article 31 of the 1969 Vienna Convention on the Law of Treaties states that "[t]he context for the purpose of the interpretation of a treaty shall comprise", in particular, "the text, including its preamble and annexes". In other words, the determination of the meaning of a particular provision is based on an examination of the treaty text as a whole, including the preamble.[9] Nonetheless, in the practice of the ILO, preambles have rarely been used for the purpose of interpreting the scope of a given provision of a Convention, neither in the opinions given by the Office upon the request of a member State nor in comments of the Committee of Experts on the Application of Conventions and Recommendations (CEACR) in its examination of the application of a particular Convention. Thus, the fact that a preamble of a Recommendation states that it supplements a Convention has been taken to imply that it would hardly be possible for it to contain provisions that are not compatible with those of the Convention itself.[10] In another case, the scope of the definition of "seafarers" was established with reference to the preamble of the Convention in question and to the previous ILO instruments to which it refers.[11]
[6] N. Quoc Dinh, P. Daillier, A. Pellet: Droit International Public (7th edition), L.G.D.J., Paris, 2002, p. 131.
[7] See M. K. Yasseen: L'interprétation des traités d'après la Convention de Vienne sur le droit des traités, Académie de droit international (Excerpt from the Recueil des cours, Volume III-1976), A. W. Sijthoff, Leyden, 1976, p. 35. For example, in the Case concerning rights of nationals of the United States of America in Morocco, the ICJ noted that the guarantee of equality of treatment had been included in the preamble of the Algesiras Act of 7 April 1906, and concluded that "in the light of these circumstances, it seems clear that the principle was intended to be of a binding character and not merely an empty phrase" (ICJ Reports 1952, p. 184). It is also the case that a preamble or individual clauses thereof can, through the process of development of customary international law, become binding in character. The "Martens Clause" in, for example, the preamble (in fine) of the Fourth Hague Convention respecting the Laws and Customs of War on Land of 1899, is a probative example. See also C. Rousseau: Droit international public, Tome I, Introduction et sources, Editions Sirey, Paris, 1970, p. 87.
[8] See Yasseen, op. cit., p. 35.
[9] Op. cit., p. 34. See also Competence of the International Labour Organisation in Questions relating to Agricultural Labour, PCIJ Advisory Opinion No. 2, reproduced in OB, Vol. VI, No. 10, 1922, as published in PCIJ, Series B, Nos. 2 & 3, at pp. 36-41; ILO: Report of the Committee on Maternity Protection, PR 20, ILC, 88th Session, 2000, Para. 68: the ILO's Legal Adviser considered that the preamble of a Convention could be considered as one contextual element for interpretation purposes.
[10] Opinion given by the Office concerning the Maternity Protection Convention (Revised), 1952 (No. 103), Austria, OB, Vol. XLV, 1962, No. 3, p. 244, Para. 10.
[11] Opinion given by the Office concerning the Prevention of Accidents (Seafarers) Convention, 1970 (No. 1970), Poland, OB, Vol. LVII, 1974, Nos. 2-4, p. 209, Para. 6.