1 For a brief history of IGAD's evolution and institutional development, see Weldesellassie, KI “IGAD as an international organization, its institutional development and shortcomings” (2011) 55/1Journal of African Law 1CrossRefGoogle Scholar.

2 The Agreement, art 8.

3 Id, art 9(2).

4 Id, art 10(2).

5 Id, art 10(4) and (5). In practice, however, the CoM votes if no consensus can be reached.

6 Id, art 11(1).

7 Id, art 11(2).

8 Id, arts 12 and 13.

9 Id, art 18A(b).

10 LR Helfer “Exiting treaties” (2005) 91/7 Virginia Law Review 1579 at 1582, note 4. A handbook prepared by the UN in 2003 provides: “The words denunciation and withdrawal express the same legal concept. Denunciation (or withdrawal) is a procedure initiated unilaterally by a State to terminate its legal engagements under a treaty”: UN Office of Legal Affairs Final Clauses of Multilateral Treaties Handbook UN Sales no E.04.V.3 (2003) at 109.

11 Helfer, ibid.

12 Vienna Convention on the Law of Treaties, opened for signature 23 May 1969, 1155 UNTS 331 (entered into force 27 January 1980), art 70(1).

13 Helfer “Exiting treaties”, above at note 10 at 1585.

14 Helfer briefly narrates: “In the decade leading up to the Second World War, Germany, Italy, Japan, and several other League members exercised their right to withdraw from the organization, thereby avoiding even the mild sanctions that the global body had attempted to impose … The widespread withdrawals from the League explain in part why the United Nations Charter does not contain an express denunciation clause.” Id at 1585, note 15.

15 Helfer (id at 1592, note 30) uses the following as examples from luminaries of international law scholarship. Brownlie, Ian in his Principles of Public International Law (6th ed, 2003, Oxford University Press)Google Scholar devoted only a single page (592) in his 715 page treatise to unilateral denunciation; in the three volume treatise Lauterpacht, H (ed) L Oppenheim, International Law: A Treatise (8th ed, 1955, Longman)Google Scholar, only one paragraph (at 938, para 538) is dedicated to unilateral denunciation; Rosenne, Shabtai, in his Developments in the Law of Treaties, 1945–1986 (1989, Cambridge University Press)Google Scholar did not discuss unilateral withdrawal or denunciation at all.

16 This has raised a very contentious issue as to whether the absence of an exit clause restrains the choice of states to participate and withdraw from participating in international relations through treaties: Helfer, id at 1592–95. For more understanding of the debate on whether states have the right, and whether international law allows states, unilaterally to withdraw from treaties at will, see Bradley, CA and Gulati, M “Withdrawing from international custom” (2010) 120 Yale Law Journal 202Google Scholar, available at: <http://documents.law.yale.edu/sites/default/files/Bradley%20Gulati.pdf> (last accessed 7 May 2015), in contrast with Brilmayer, L and Tesfalidet, IY “Treaty denunciation and ‘withdrawal’ from customary international law: An erroneous analogy with dangerous consequences” (2011) 120 Yale Law Journal 217Google Scholar. The debate centres on whether states have “the right to terminate (or right to withdraw)” or “the right to invoke certain grounds as a basis for withdrawal or termination”: Brilmayer and Tesfalidet, id at 222.

17 These are: treaties that may be denounced at any time; treaties that preclude denunciation for a fixed number of years, calculated either from the date the agreement enters into force or from the date of ratification by the state; treaties that permit denunciation only at fixed time intervals; treaties that may be denounced only on a single occasion, identified either by time period or upon the occurrence of a particular event; treaties whose denunciation occurs automatically upon the state's ratification of a subsequently negotiated agreement; and treaties that are silent as to denunciation or withdrawal: Helfer, id at 1597.

18 Schwelb, E “Withdrawal from the United Nations: The Indonesian intermezzo” (1967) 61/7American Journal of International Law 661CrossRefGoogle Scholar at 666.

19 American Society of International Law “Return of Indonesia to the United Nations” (November 1966) 5/6International Legal Materials 1186CrossRefGoogle Scholar at 1187.

20 Schwelb “Withdrawal from the United Nations”, above at note 18 at 667–68.

21 Ibid.

22 Id at 667. The interpretive declaration made by the First Commission of the San Francisco conference that led to the establishment of the UN read: “The Committee [Committee I/2 which handled the issue of withdrawal] adopts the view that the Charter should not make express provision either to permit or prohibit withdrawal from the Organization … If, however, a Member because of exceptional circumstances feels constrained to withdraw, and leave the burden of maintaining international peace and security on the other Members, it is not the purpose of the Organization to compel that Member to continue its cooperation in the Organization.” See Kelsen, H “Withdrawal from the United Nations” (1948) 1/1Western Political Quarterly 29CrossRefGoogle Scholar at 29.

23 American Society of International Law “Return of Indonesia”, above at note 19 at 1186.

24 Schwelb “Withdrawal from the United Nations”, above at note 18 at 668–69.

25 Helfer Exiting Treaties, above at note 10 at 1595.

26 Blum, YZ “Indonesia's return to the United Nations” (1967) 16/2International and Comparative Law Quarterly 522CrossRefGoogle Scholar at 525–31.

27 Id at 529. See below at notes 28 and 32.

28 Sohn, LB “Expulsion or forced withdrawal from an international organization” (1964) 77/8Harvard Law Review 1382CrossRefGoogle Scholar at 1398.

29 Id at 1406.

30 Cuba, for instance, has remained an official member of the Organization of American States (OAS) since 1962 when it was suspended because of its relationship with the Soviet Union and China. In July 2009, Cuba rejected an OAS resolution to “readmit” it. See also the example of South Africa and its suspension from the UN in “Membership – Suspension and expulsion”, available at: <http://www.nationsencyclopedia.com/United-Nations/Membership-SUSPENSION-AND-EXPULSION.html> (last accessed 7 May 2015).

31 Sohn “Expulsion or forced withdrawal”, above at note 28 at 1391–92.

32 Id at 1396–97. See for instance the example of South Africa in “South Africa and the Commonwealth”, available at: <http://www.dfa.gov.za/foreign/Multilateral/inter/commonwealth.htm> (last accessed 3 August 2012).

33 Sohn, id at 1405–06.

34 Id at 1412–15.

35 Id at 1409.

36 ECOSOC official record 34th sess, supp no 10, 39–41 (E/3586) (1962), referred to in id at 1409, note 142.

37 UN doc no E/3820 (1963), referred to in id at 1410, note 143.

38 ECOSOC official record 36th sess 199 (USSR) (1962) 202, referred to in id at 1410, note 144.

39 Ibid.

40 Id at 1410–11.

41 Id at 1411–12.

42 Letter from Eritrean Ministry of Foreign Affairs to the then AHSG chair, ref: AAP/220/07, 27 April 2007 (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

43 Ibid.

44 For a brief narration of the post-1991 Somalia problem and attempts to solve it, see K Mulugeta “The role of regional and international organizations in resolving the Somali conflict: The case of IGAD”, available at: <http://library.fes.de/pdf-files/bueros/aethiopien/07937-book.pdf> (last accessed 15 May 2015); “Somali peace process”, available at: <http://amisom-au.org/about-somalia/somali-peace-process> (last accessed 15 May 2015); X Rice “Ethiopian troops sent into Somalia to halt Islamist advance” (21 July 2006) The Guardian, available at: <http://www.guardian.co.uk/world/2006/jul/21/mainsection.international11> (last accessed 1 August 2012); “Ethiopian troops enter Somalia to resist Islamic militia” (20 July 2006) PBS, available at: <http://www.pbs.org/newshour/updates/africa-july-dec06-somalia_07-20/> (last accessed 15 May 2015); A Talbot “Ethiopian troops occupy Mogadishu” (30 December 2006) World Socialist Web Site, available at: <http://www.wsws.org/en/articles/2006/12/soma-d30.html> (last accessed 7 May 2015); “Brief history [of African Union Mission in Somalia]”, available at: <http://amisom-au.org/about-somalia/brief-history/> (last accessed 7 May 2015).

45 P Clottey “Eritrea tells why it left - and rejoined - regional bloc” (7 June 2012) Voice of America, available at: <http://www.voanews.com/content/eritrea-explains-history-with-regional-bloc/1204715.html> (last accessed 1 August 2012). Text of the CoM statement is available at: <http://www.allsanaag.com/index.php/component/content/article/25-somalia-and-amisom/172-maxkamaduhu-alshayaadiin-iyo-itoobiya> (last accessed 1 August 2012).

46 Mulugeta “The role of regional and international organizations”, above at note 44 at 33–34; W Ross “Ethiopian troops ‘cross border into Somalia’” (19 November 2011) BBC News, available at: <http://www.bbc.co.uk/news/world-africa-15807215> (last accessed 7 May 2015); J Gettleman “Ethiopian troops said to enter Somalia, opening new front against militants” (20 November 2011) New York Times, available at: <http://www.nytimes.com/2011/11/21/world/africa/ethiopian–troops–enter–somalia–witnesses–say.html> (last  accessed 2 August 2012).

47 Text of the resolution is available at: <http://www.un.org/News/Press/docs/2009/sc9833.doc.htm> (last accessed 7 May 2015).

48 Comm of 27th ordinary session (12 June 2008) at 16 (emphasis added).

49 Id at 17 (emphasis added).

50 Id at 18.

51 Proceedings of the 12th AHSG summit: IGAD/SUM–12/2008–PROC at 4.

52 Id at 6 (emphasis added).

53 Id at 9 (emphasis added).

54 Id at 23 (emphasis added).

55 Id at 44 (emphasis added).

56 Report of the Mission of the IGAD ministers of foreign affairs and executive secretary to Eritrea at 2 (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

57 Id at 2–3.

58 Id at 3–4.

59 Id at 4.

60 Ibid.

61 Ibid.

62 Ibid.

63 IGAD press release “Visit of IGAD ministers and ES to Eritrea” (emphasis added) (16 August 2008), available at: <http://igad.int/index.php?option=com_content&view=article&id=115:press-release-visit-of-igad-ministers-and-es-to-eritrea&catid=47:communique&Itemid=149> (last accessed 4 August 2012).

64 Letter ES10–400/AD 013/11, 20 July 2011. A copy of the 27 July 2011 letter referring to this letter is on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA.

65 More detailed information on the project, which is part of the world hydrological cycle observing system developed by the World Meteorological Organization, is available at: <http://www.whycos.org/whycos/documents/igad-hycos-rev-project_documents_2012.pdf> (last accessed 11 May 2015).

66 Letter from Mr Osman Saleh, Eritrea's foreign minister, to Eng Mahboub M Maalim, IGAD executive secretary, (no reference number) 25 July 2011 (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

67 Letter from Mr Osman Saleh, Eritrea's foreign minister, to Dr Jean Ping, AU Commission chair, ref: MO/114/2011, 18 October 2011 (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

68 Letter from Eng Mahboub Maalim, IGAD executive secretary, ES20–103/328 (28 July 2011) (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

69 Ibid.

70 Letter ES40–100/324/11, 27 July 2011 (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

71 Djibouti, Eritrea, Ethiopia, Kenya, Somalia, Sudan and Uganda.

72 Letter from Mr Osman Saleh, Eritrea's foreign minister, to Eng Mahboub M Maalim, IGAD executive secretary, ref: MO/300/2011, 30 July 2011 (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

73 Comm of the 40th CoM extraordinary session, para 10 at 5 (emphasis added).

74 “Eritrean representative suspended from IGAD ministrs [sic] meeting” (YouTube record of Ethiopian television news of the incident aired in Amharic), available at: <https:// www.youtube.com/watch?v=KI7SOZ8Kp5Q> (last accessed 15 May 2015).

75 Betre-Sltan “IGAD dismisses Eritrean diplomat from its meeting” (translation of news in Tigrigna) (25 August 2011), available at: <http://tigrigna.voanews.com/content/igad-eritrea-addis-ababa-biniam-berhe-128413023/1383269.html> (last accessed 15 May 2015).

76 “South Sudan applies for IGAD membership” (11 July 2011) Catholic Radio Network, available at: <http://catholicradionetwork.org/?q=node/4374> (last accessed 7May 2015).

77 Comm of AHSG's 19th extraordinary session at 3.

78 Letter from Mr Osman Saleh, Eritrea's foreign minister, to Eng Mahboub M Maalim, IGAD executive secretary, ref: MO/227/2011, 24 October 2011 (copy on file with the author, courtesy of the Mission of the State of Eritrea to the AU and ECA).

79 Letter from Mr Osman Saleh to Dr Jean Ping, above at note 67.

80 Ibid.

81 Ibid.

82 Ibid.

83 Comm of AHSG's 19th extraordinary session at 7.

84 Comm of AHSG's 20th extraordinary session at 4.

85 Comm of the 45th CoM extraordinary session at 2.

86 Comms of the 33rd CoM extraordinary session: Ext Ord 1 (20 May 2009), paras 5 and 6, Ext Ord 2 (20 May 2009), para 4 and Ext Ord 3 (10 July 2009), para 9; comm of AHSG's 14th extraordinary session (30 June 2009), para 4; comms of the 33rd CoM ordinary session: general (7–8 December 2009) at 2, on Somalia (7–8 December 2009), paras 6 and 27.

87 Comm of the 190th meeting of the AU Peace and Security Council (22 May 2009), paras 4 and 5(ii).

88 Comm of AHSG's 18th extraordinary session (4 July 2011) at 5.

89 I Van Damme “Treaty interpretation revisited, not revised” (International Labour Organization Distinguished Scholar Series, 30 October 2008) at 1, available at: <http://www.ilo.org/public/english/bureau/leg/include/home/van_damme.pdf> (last accessed 7 May 2015). On the universal acceptance of arts 31–33 of the Vienna Convention, Qureshi states that “The [Vienna Convention] is certainly generally uncritically invoked”: Qureshi, AHInterpreting WTO Agreements: Problems and Perspectives (2006, Cambridge University Press)CrossRefGoogle Scholar at 4.

90 “United States: Standards for reformulated and conventional gasoline” (appellate body report) WT/DS2/AB/R at 16. Referring to: the Territorial Dispute Case (Libyan Arab Jamahiriya v Chad) (1994) ICJ report at 6 (International Court of Justice); Golder v United Kingdom ECHR, series A, (1995) no 18 (European Court of Human Rights); Restrictions to the Death Penalty cases (1986) 70 International Law Reports 449 (Inter–American Court of Human Rights); de Aréchaga, J “International law in the past third of a century” (1978) 159 Recueil des Cours 1Google Scholar at 42; Carreau, DDroit International [International Law] (3rd ed, 1991, Pédone)Google Scholar at 140; Jennings, R and Watts, A (eds) Oppenheim's International Law vol 1 (9th ed, 1992, Longman)Google Scholar at 1271–75. See also Qureshi, id at 5, note 14. Van Damme states that the principles of interpretation in arts 31–33 of the Vienna Convention “bind all States as customary international law” but that “[f]rom a formal perspective, they are part of binding treaty language for the contracting parties to the Vienna Convention”: Van Damme, id at 5.

91 See for instance, Hall's 1916 article: Hall, JP “The force of precedents in international law” (1916) 26/2International Journal of Ethics 149CrossRefGoogle Scholar. For the practice of the use of precedents in the International Court of Justice, the World Trade Organization dispute settlement organs and the International Center for the Settlement of Investment Disputes, see A Reinisch “The role of precedent in ICSID arbitration”, available at: <http://investmentarbitration.univie.ac.at/fileadmin/user_upload/int_beziehungen/Personal/Publikationen_Reinisch/role_precedents_icsid_arbitrationaayb_2008.pdf> (last accessed 7 May 2015) at 5–15; Shahabuddeen, MPrecedent in the World Court, vol 13 of Hersch Lauterpacht memorial lectures (2007, Cambridge University Press)Google Scholar; Glenn, HP “Persuasive authority” (1987) 32/2McGill Law Journal 255Google Scholar at 261; Guillaume, G “The use of precedent by international judges and arbitrators” (2011) 2/1Journal of International Dispute Settlement 5CrossRefGoogle Scholar.

92 Helfer Exiting Treaties, above at note 10 at 1595.

93 D Guodong “Singapore rejoins UNESCO” (8 October 2011) China View, available at: <http://news.xinhuanet.com/english/2007-10/08/content_6847848.htm> (last accessed 7 May 2015); “Singapore rejoins UNESCO after a gap of 22 years” (9 October 2007), available at: <http://timesofindia.indiatimes.com/world/us/Singapore-rejoins-UNESCO-after-a-gap-of-22-years/articleshow/2441676.cms?> (last accessed 11 May 2015).

94 “Eritrea breaks with African Union”, available at: <http://www.afrol.com/articles/10577> (last accessed 9 August 2012).

95 “Eritrea reopens African Union Mission” (18 January 2011) Voice of America, available at:<http://www.voanews.com/content/eritrea-reopens-african-union-mission-114212594/157253.html> (last accessed 9 August 2012).

96 AU press release “The chairperson of the African Union Commission receives the credentials of the permanent representatives of Eritrea”, available at: <http://www.au.int/en/sites/default/files/PR_NO_EN_17_JANUARY_2011_CP_CHAIRPERSON_AFRICAN_UNION_COMMISSION_RECEIVES_CREDENTIALS_PERMANENT_REPRESENTATIVES_ERITREA.pdf > (last accessed 15 May 2015).

97 In the interpretation of treaties, international tribunals often refer to the preamble in the course of interpreting the treaty at hand. Gross states: “it must be admitted that an international tribunal may and often does find guidance in the preamble of a treaty which sets forth the agreed objectives of the parties, in the principles of international law and the general principles of law”: Gross, L “Treaty interpretation: The proper role of an international tribunal” (April 1969) 63 Proceedings of the American Society of International Law 108Google Scholar at 115. In its commentary on what would later become art 31 of the Vienna Convention, the International Law Commission underlined that the preamble of a treaty is part of the “context” of a treaty: “That the preamble forms part of a treaty for purposes of interpretation is too well settled to require comment”: International Law Commission Draft Articles on the Law of Treaties with Commentaries ILC Yb 1966, vol II at 221Google Scholar.

98 The Agreement, art 6A.

99 Id, art 7.

100 Art 26 of the Vienna Convention provides: “Every treaty in force is binding upon the parties to it and must be performed by them in good faith.”

101 Certain Norwegian Loans (France v Norway) (jurisdiction) [1975] ICJ reports 9 at 53.

102 The different sessions of the AHSG and CoM after July 2011 discussed Eritrea and frequently made recommendations against it, but never raised the issue of the resumption of its participation in IGAD.

103 International Crisis Group “Eritrea: Scenarios for future transition” (Africa report no 200, 28 March 2013) at i, available at: <http://www.crisisgroup.org/~/media/Files/africa/horn-of-africa/ethiopia-eritrea/200-eritrea-scenarios-for-future-transition.pdf> (last accessed 15 May 2015).