A. Introduction

UNITED

NATIONS

A

General Assembly Distr.

LIMITED

A/CN.4/L.702

18 July 2006

Original: ENGLISH

INTERNATIONAL LAW COMMISSION

Fifty-eighth session

Geneva, 1 May-9 June and 3 July-11 August 2006

FRAGMENTATION OF INTERNATIONAL LAW: DIFFICULTIES

ARISING FROM THE DIVERSIFICATION AND EXPANSION OF

INTERNATIONAL LAW

Report of the Study Group of the International Law Commission

A. INTRODUCTION

1. At its fifty-fourth session (2002), the International Law Commission established a Study

Group to examine the topic “Fragmentation of international law: difficulties arising from the

diversification and expansion of international law”. 1 At its fifty-fifth session (2003), the Study

Group adopted a tentative schedule for work to be carried out during the remaining part of the

present quinquennium (2003-2006) and allocated to five of its members the task of preparing

outlines on the following topics:

(a) “The function and scope of the lex specialis rule and the question of

self-contained regimes” (Mr. Koskenniemi);

1 Official Records of the General Assembly, Fifty-seventh Session, Supplement No. 10 (A/57/10),

paras. 492-494.

GE.06-62863 (E) 200706

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(b) The interpretation of treaties in the light of “any relevant rules of international law

applicable in the relations between the parties” (article 31 (3) (c) of the Vienna Convention on

the Law of Treaties), in the context of general developments in international law and concerns of

the international community (Mr. Mansfield);

(c) The application of successive treaties relating to the same subject matter

(article 30 of the Vienna Convention on the Law of Treaties) (Mr. Melescanu);

(d) The modification of multilateral treaties between certain of the parties only

(article 41 of the Vienna Convention on the Law of Treaties) (Mr. Daoudi); and

(e) Hierarchy in international law: jus cogens, obligations erga omnes, Article 103 of

the Charter of the United Nations, as conflict rules (Mr. Galicki).

2. During its fifty-sixth (2004) and fifty-seventh session (2005), the Study Group received

a number of outlines and studies on these topics. It affirmed that it was its intention to prepare,

as the substantive outcome of its work, a single collective document consisting of two parts.

One would be a “relatively large analytical study” by the Chairman that would summarize

and analyse the content of the various individual reports and the discussions of the

Study Group. This bulk of the report prepared by the Chairman in 2006 is contained in

document A/CN.4/L.682. The other part would be “a condensed set of conclusions, guidelines

or principles emerging from the studies and discussions in the Study Group”. 2 As the

Study Group itself held, and the Commission endorsed, this should consist of “a concrete,

practice-oriented set of brief statements that would work, on the one hand, as the summary and

conclusions of the Study Group’s work and, on the other hand, as a set of practical guidelines to

help thinking about and dealing with the issue of fragmentation in legal practice”. 3

3. During the current fifty-eighth session of the Commission, the Study Group was

reconstituted; it held 10 meetings on 17 and 26 May, on 6 June, on 4, 11, 12, 13 and

2 Ibid., Sixtieth Session, Supplement No. 10 (A/60/10), para. 448.

3 Ibid.

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17 July 2006; and it completed its work. Section C sets out the conclusions of the Study Group. 4

They are a result of the extensive deliberations the Study Group had undertaken between 2004

and 2006. They are a collective product by the members of the Study Group.