Australian Year Book of International Law
It is a great pleasure to be able to contribute to the volume of this Year Book in honour of Professor Donald Greig. This student of international law had the benefit of being taught the Law of Treaties on the LL.M. at Kings College London by Professor Greig in 1991–1992. His rigour and kindness were very greatly appreciated.
The United Nations (UN) Secretary-General is among the foremost contributors to the processes directed at maintaining or restoring international peace and security. The Secretary-General makes this contribution as a principal organ of the UN in a variety of ways that range from the exercise of his or her own express and implied powers under the Charter through to the exercise of powers and functions that have been delegated to the Secretary-General by the UN Security Council or General Assembly. Although there has been considerable discussion in the literature concerning the role of the Secretary-General in the maintenance of peace and security more generally, there has, however, been relatively little focus on the important role of the Secretary-General concerning UN peace-keeping operations. It is this subject that is the focus of our present discussion.
It is clear that UN peace-keeping forces are UN subsidiary organs. Moreover all UN peace-keeping forces with the exception of the UN Emergency Force (UNEF I), established by the General Assembly in Resolution 1000, have been established by, or under the authority of, the Security Council. In these cases of UN peace-keeping, it has, to date, been the consistent practice of the Council to delegate to the Secretary-General its powers both to establish and to exercise command and control powers over the force. Accordingly, in discussing the role of the Secretary-General in UN peace-keeping operations it is necessary to focus on the legal considerations relating to these delegations of power by the Security Council to the Secretary-General. An exploration of these delegations requires discussion of three main areas: the scope of the competence of the Council to delegate in the first place its powers to the Secretary-General; the construction of the legal framework governing the exercise of these powers by the Secretary-General; and an analysis of the practice of the Council when delegating powers to the Secretary-General concerning UN peace-keeping and the practice of the Secretary-General in exercising these powers.
A preliminary issue that needs to be considered briefly before turning to such issues of delegation is the characterisation of the legal basis of UN peace-keeping forces under the Charter. This is of importance since the legal basis will determine the nature and scope of limitations that constrain the Council’s use of peace-keeping forces and the role of the Secretary-General acting as its delegate.
It is clear that UN peace-keeping does not, at least in theory, involve the use of military ‘enforcement action’ against a state. This does not, however, preclude the characterisation of the establishment and operation of UN peace-keeping forces as being an exercise by the Council of implied powers under Chapter VII of the Charter, since not every measure under Chapter VII has to involve military enforcement action. There are two reasons why this characterisation should be made. First, the powers of the Council concerning peace-keeping can be implied from the object and purpose of Chapter VII that the Council should be able to take such action as it deems necessary to maintain or restore peace and security. The International Court of Justice (ICJ) employed such an approach when discussing the legality of UN peace-keeping operations in the Expenses Case:
Articles of Chapter VII of the Charter speak of “situations” as well as disputes, and it must lie within the power of the Security Council to police a situation [i.e., conduct peace-keeping] even though it does not resort to enforcement action against a State.
Second, the characterisation of UN peace-keeping as a Chapter VII measure is also supported, importantly, by the subsequent practice of the Security Council.  When establishing UN peace-keeping forces the Council has very often made an Article 39 determination, the prerequisite for the use of its Chapter VII powers, that the situation which calls for the deployment of the force constitutes a threat to peace and security.
Let us now turn to discuss the scope of the competence of the Council to delegate its Chapter VII powers concerning UN peace-keeping to the Secretary-General.
It is one thing for a UN principal organ to possess a particular power, but it is another for that organ to be able to delegate that power. To be able to delegate powers an organ of an international organisation must possess either the express or implied competence to do so under its constituent treaty. Moreover, an organ of an international organisation cannot delegate powers that it does not itself possess. This derives from the general principle of law nemo dat quod non habet: one cannot give what one does not possess. Accordingly, both the possession by an organ of an international organisation of either an express or implied power and the competence to delegate this power are necessary preconditions for a lawful delegation of power to occur.
There is, however, no express provision in the Charter that provides the Council with the competence to delegate its Chapter VII powers to other principal organs and in particular to the Secretary-General. However, it has been explained at length elsewhere that the Council does possess a general competence to delegate its Chapter VII powers to other entities that are part of the Organisation,[17 ]which of course includes the Secretary-General. The Council’s general competence to delegate Chapter VII powers is, moreover, supported in the case of the Secretary-General by reference to an implied powers approach under Article 98 of the Charter and the subsequent practice of the Council in consistently delegating these powers to the Secretary-General. However, the competence of the Council being able to delegate its Chapter VII powers to the Secretary-General does not mean that there are no restrictions on this competence.
There are significant general limitations on the competence of the Council being able to delegate its Chapter VII powers to other entities. These have been examined in detail elsewhere, but that which is of particular relevance to our discussion is that the Council can delegate a broad power of discretion only if it retains the right at all times to change decisions and policy approaches to decisions of its delegate. The observance of this limitation by the Council is necessary for a delegation of Chapter VII powers to be lawful, and its observance in the context of the Secretary-General is considered below in Section III.
A lawful delegation of Chapter VII powers to the Secretary-General may still impose legal limitations on the Secretary-General when exercising these powers. The following section establishes the contours of the legal framework that governs the exercise of these Chapter VII powers by the Secretary-General once a lawful delegation of powers has taken place.
There are three main areas that need to be addressed when constructing the legal framework governing the exercise by the Secretary-General of delegated Chapter VII powers. First, the competence of the Secretary-General to exercise such powers. Second, the limitations that constrain the Secretary-General when exercising these powers. Third, legal aspects of the interpretation by the Secretary-General of the delegated powers.
In theory the Secretary-General may not possess the competence under the Charter to exercise all the powers which the Council may wish to delegate to him or her. The lawful delegation by the Council of Chapter VII powers to an entity does not automatically mean the entity has the competence to exercise these powers. The main objection that has been made to the exercise by the Secretary-General of delegated Chapter VII powers is that the Secretary-General does not possess the institutional competence under the Charter to exercise discretionary Chapter VII powers of decision-making or to make ‘policy decisions’. However this argument is unconvincing for the following reasons. First, the Secretary-General already possesses a discretionary power of decision-making under Article 99 of the Charter. Article 99 of the Charter provides that the Secretary-General ‘may bring to the attention of the Security Council any matter which in his opinion may threaten the maintenance of international peace and security’. The decision by the Secretary-General whether a particular issue constitutes a threat to peace and security is the same type of policy decision or discretionary power of decision-making that the Council possesses under Article 39 of the Charter.[25 ]It is just that the consequences of this decision being made by the Council as opposed to the Secretary-General are different. Second, the view that the Secretary-General can exercise discretionary powers is validated also by UN practice. Third, the legality of the Secretary-General exercising a power of discretion has been upheld in express terms by the UN Administrative Tribunal in the case of, among others, Peynado v Secretary-General.  Having regard to these three factors it is contended that the Secretary-General does possess the competence to exercise delegated Chapter VII powers.
The limitations that restrict the exercise by the Secretary-General of delegated Chapter VII powers are both express and implied.
The express limitations are those contained in the Council resolution that is the source of the delegated power. The Secretary-General would be exercising powers that he or she does not possess under the Charter if he or she acted beyond the mandate given by the Council, since the Secretary-General does not possess the authority to exercise Chapter VII powers without a delegation of such powers from the Council.
The implied limitations are not specific to the case of delegation: they are general limitations that apply to the exercise of any discretionary powers by the Secretary-General. These limitations are twofold. First, the Secretary-General is under an obligation to exercise a power of discretion in good faith. When exercising a delegated power of discretion, the Secretary-General must be presumed to fulfil this requirement. Second, the opinions of UN member states cannot constitute a sole basis for decision-making by the Secretary-General. UN members can of course convey views to the UN which may subsequently provide a basis for a decision by a UN organ or its delegate. However, the view of UN member states cannot constitute the sole basis for the decision by a UN organ such that it does not itself exercise its power of discretion and make a decision in accordance with its stipulated decision-making processes. This rule which exists as part of the law of international institutions flows from the independence of an international organisation from its member states. The independence of the Secretary-General from member states is expressly provided for in Article 100 of the Charter, and thus, as a former Secretary-General has contended, the Secretary-General must exercise a power of discretion having regard to what the Secretary-General considers to be in the best interests of the Organisation and not solely in the interest of any particular state or group of states.
The way in which delegated powers are to be exercised is rarely specified when the Council or Assembly delegate powers to the Secretary-General. The lack of clarity in Council resolutions that delegate powers arises from the fact that the resolutions often reflect a political compromise by member states. However, once a delegation of powers has occurred then the Secretary-General can imply certain additional powers from the terms of the delegation. This power of interpretation is necessary for the effective exercise by the Secretary-General of powers which he or she has been expressly delegated. When interpreting a delegated mandate the Secretary-General often makes reports to the Council that are subsequently adopted by the Council in a resolution. Once adopted, the Secretary-General will often use the report to provide evidence that the Council supports his or her particular interpretation of the way in which delegated powers are to be used.
A former Secretary-General has correctly stated that his interpretation of delegated Chapter VII powers could only be challenged in the Security Council. A consequence of this is that until the Council makes a decision contrary to the Secretary-General’s interpretation then the latter is binding on UN member states. The difficulty in obtaining an express interpretation from the Council as to the content of the Secretary-General’s delegated powers will often mean that in practice the Secretary-General exercises a power of authoritative interpretation over his or her delegated powers. Moreover, the interpretation that the Secretary-General gives to his or her delegated mandate is not subject to agreement or negotiation with UN member states. Ever since the UN Operation in Congo (ONUC) it has been established that any discussions the Secretary-General may undertake with states are limited only to facilitating the implementation of the mandate by working out the modalities and by eliminating possible obstacles, but they can never amount to renegotiating the mandate or to imposing on the Secretary-General a certain interpretation of it.
The Security Council has delegated two types of power to the Secretary-General in connection with UN peace-keeping operations: the power to establish peace-keeping forces, and the power to exercise command and control over these forces.
The UN Charter does not provide in express terms for the establishment or use of UN peace-keeping forces. However, the ICJ in the Expenses Case found that the Council has an implied power to establish UN peace-keeping forces. The Court also found that the Council has the competence to delegate to the Secretary-General the power to establish peace-keeping forces. This delegation is necessary for the Secretary-General to establish such forces, since he or she does not possess the competence otherwise. Accordingly, the establishment of UN peace-keeping forces by the Secretary-General represents the exercise of a delegated power. In every case where the Council has established a UN peace-keeping force it has delegated to the Secretary-General its Chapter VII power to establish such a force.As the legal basis for, and mandate of, a UN peace-keeping force are rooted in a resolution of either the Council or the Assembly, it follows that the Secretary-General does not possess the competence unilaterally to terminate a UN peace-keeping force — a subsidiary organ under the overall authority and control of another UN principal organ — or change its mandate unless these powers have been expressly delegated to him or her by the relevant principal organ.
The Council does not usually delegate to the Secretary-General in express terms the power to determine the composition of a UN peace-keeping force. This is a power that the Secretary-General implies as being necessary for the effective exercise of the delegated power of establishment. The International Court approved this approach in the Expenses Case when it rejected the contention of the former Soviet Union that the Secretary-General had acted illegally in determining the composition of ONUC without a prior express authorisation from the Council. In practice the Secretary-General when establishing peace-keeping forces has often asserted an exclusive competence vis-à-vis UN member states to determine the composition of a force in the face of opposition by member states who have disagreed with the composition of a particular peace-keeping force.
The Charter provides a framework for decision-making by the Council when exercising command and control powers over a UN force that is carrying out military enforcement action. Specifically, Articles 46 and 47 envisage a role for the Military Staff Committee when the Council is making decisions concerning the use of military force. Moreover, Article 44 of the Charter requires the Council to give a state that has contributed troops to a military enforcement force the ability to participate in decisions of the Council concerning the use of that state’s troops. However, it seems clear that these Charter provisions do not apply in the case of UN peace-keeping forces, since such forces do not involve enforcement action. This approach was confirmed in the Expenses Case where the Court found that since peace-keeping operations were not ‘enforcement actions within the compass of Chapter VII of the Charter’ ‘that therefore Article 43 [a mechanism for providing troops to the Council to use in carrying out enforcement action] could not have any applicability’. Similarly, Articles 44, 46, and 47 of Chapter VII which relate to the use of a military enforcement force by the Council are inapplicable in the case of UN peace-keeping. The Security Council thus exercises an exclusive authority and control over UN peace-keeping forces.
The delegation of powers of command and control over a force to the Secretary-General is necessary for the Secretary-General to exercise such powers since he or she does not have the competence to assume powers of command and control under his or her own authority. Once such a delegation has taken place the Secretary-General assumes the role of overall commander of the force. There can be no legal objection, as already explained, to the use by the Council of its general competence to delegate such powers to the Secretary-General. There has, moreover, been a consistent course of practice where the Council has delegated its powers of command and control to the Secretary-General.
As early as 1956, in the case of UNEF, the Secretary-General exercised strategic and political control over a UN peace-keeping force. Similarly, in the second case of UN peace-keeping, in the Congo, the Secretary-General exercised authority and control over ONUC, the Secretary-General having made it clear that command and control over ONUC lay exclusively in the hands of the UN and not the host state or any contributing or other member state. In the case of the Congo, the consequences of the delegation of command and control powers by the Council to the Secretary-General had two major consequences. First, it led to intense criticism of the role of the Secretary-General, and even led some states, notably the former Union of Soviet Socialist Republics (USSR), to call for the replacing of a single Secretary-General by a ‘troika’, and a separate proposal to transfer operational control from the Secretary-General to a ‘unified African command’ directly responsible to the Security Council. Both these proposals failed to gain significant support among UN members. Second, and more serious, was the consequence that states that contributed troops to the peace-keeping force attempted to force changes in the policies of the Secretary-General. Such attempts to force changes in policy are not of course objectionable when conducted within the confines of a deliberative political organ of the UN such as the Council. However once states have contributed troops to a peace-keeping force, the attempt by states to pressure the Secretary-General either by threatening to cease to execute the orders of the UN Command, or to impose unilaterally the conditions on which their national contingents can be used, are all of dubious legality. As explained above, if a state holds a differing interpretation of the mandate of a peace-keeping force from that of the Secretary-General the appropriate forum to raise the issue is the Council. A state cannot instruct its national commander who is part of a UN peace-keeping force to disobey the orders of the Force Commander, the Secretary-General’s delegate.
The absence of a legal requirement for the Secretary-General to take into consideration the views of member states in the way that he or she exercises the command and control powers that he or she has been delegated is subject to the practical consideration that UN peace-keeping forces are consent-based. Accordingly, the Secretary-General in practice will have to take into consideration, to some extent at least, the views of states that have contributed troops to such a force. This political requirement saw, in the cases of UNEF and ONUC, the establishment of ‘Advisory Committees’ constituted of states that had contributed troops to the peace-keeping forces. These Committees were consulted by the Secretary-General on the way in which the peace-keeping forces were to be used. However, there have been no Advisory Committees established since these cases. Nonetheless, the Secretary-General has continued to take account of the views of states despite the absence of a formal mechanism for these views to be expressed. The use of Advisory Committees remains a desirable institutional innovation that the Secretary-General or Security Council should re-institute. This would help prevent the case where commanders of a national contingent receive instructions from their national command structure that are contrary to those issued by the UN Force Commander.
The Secretary-General exercises command and control over peace-keeping forces in practice by use of a Special Representative and a Force Commander. These UN Officials, as part of the UN Secretariat, are under the authority and control of the Secretary-General. The mandate of the Special Representative is usually formulated by the Secretary-General or, in exceptional cases, by the Council itself. The usual practice is that the Council simply endorses the plan put before it by the Secretary-General.
The Special Representative exercises political control over UN peace-keeping troops in the field; while the Force Commander translates the political directives emanating from the Secretary-General and the Special Representative into military commands that are given to the national commanders of each national contingent. In every peace-keeping operation the Secretary-General delegates powers — either through the Special Representative or directly — to the Force Commander. The Summary Study by Secretary-General Hammarskjold in respect of UNEF states that the Force Commander is the principal agent of the Secretary-General within the area of operations. These broad sub-delegations of power by the Secretary-General to a Special Representative and a Force Commander are not prima facie unlawful. The reason for this derives from the status of Special Representatives and Force Commanders as part of the UN Secretariat, under the authority and control of the Secretary-General. As a result the Council, through the Secretary-General, can exercise unchallengeable authority and control over the decisions of the delegate. This position is important since, as noted above, the Council can delegate a broad power of discretion only if it retains the right to change decisions, or a policy approach to decision-making, by its delegate. However, whether the Secretary-General can lawfully sub-delegate powers in a particular case will depend on the existence of an express or an implied competence to do so.
The delegation by the Secretary-General of powers of command and control over peace-keeping forces to a Special Representative and Force Commander is a necessary and important way in which the effective exercise of delegated Chapter VII powers can be carried out. This is borne out by the extensive practice of the Secretary-General in making such delegations. An important recent element of this practice has been the delegation to a Special Representative and Force Commander of the competence to order the use of force in defence of UN peace-keepers.
It is generally accepted that the use of force by UN peace-keepers in self-defence is lawful. It is not proposed to enter into discussion here of the outer limits of this right. The present discussion is limited to examining the role of the Secretary-General when a power to use force in defence of UN peace-keepers has been given by the Council to entities external to the UN. The Council has delegated such a power to other entities in respect of the UN Protection Force (UNPROFOR) in Bosnia. The Council in paragraph 10 of resolution 836 (1993) provided:
that … Member States, acting nationally or through regional organizations or arrangements, may take, under the authority of the Security Council and subject to close coordination with the Secretary-General and UNPROFOR, all necessary measures, through the use of air power, in and around the safe areas in … … to support UNPROFOR in the performance of its mandate…
The resolution makes clear in other provisions that member states and regional organisations can use air power to respond to attacks on both UNPROFOR and the UN declared ‘safe-areas’ in Bosnia. What is not so clear, however, from the terms of the resolution is who should decide when force should be used. The Secretary-General took this decision upon himself as, in effect, the representative of the UN. After noting in a report to the Council that the North Atlantic Treaty Organization (NATO) had confirmed its willingness to offer ‘protective air power in the case of attack against UNPROFOR in the performance of its overall mandate, if it so requests’, the Secretary-General further noted: ‘It is of course understood that the first decision to initiate the use of air resources in this context will be taken by the Secretary-General in consultation with the members of the Security Council.’ This report, and thus the Secretary-General’s interpretation, was expressly adopted by the Council in paragraph 1 of resolution 844 (1993). As explained above, the adoption by the Council of a Secretary-General’s report where a specific interpretation is made of a delegated mandate is taken by the Secretary-General to represent an affirmation by the Council of that interpretation. In any case the consent of the Secretary-General is required by law. The position of the Secretary-General as Commander-in-Chief of UN peace-keeping forces means that any use of force in defence of UN peace-keepers, here ‘close air support’, would require either his or her consent or that of his or her Special Representative or Force Commander who may have been delegated this power of decision-making. The practice of the UN and NATO in the former Yugoslavia has been in accordance with this legal position. The use of close air support required a request for such action by peace-keepers who were the subject of an attack. The request then went to the Force Commander and finally to the Special Representative for the final decision as to whether close air support should be requested from NATO, the Secretary-General having decided to delegate the competence to request the use of close air support to his Special Representative.
There was, however, no express request from the Council to the Secretary-General to delegate this power of command and control to the Special Representative. Thus for the Secretary-General to be able to delegate these powers to a Special Representative or a Force Commander the Secretary-General must possess an implied competence to do so. The main condition for the existence of such a competence is that the sub-delegation must be necessary for the performance by the Secretary-General of his or her delegated powers and functions. This functional necessity is the essential element that must exist for there to be an implied power under the law of international organisations. The determination of whether this is the case will be made, at least in the first instance, by the Secretary-General. In the case of the former Yugoslavia, the Secretary-General stated that the delegation of power to his Special Representative ‘is necessitated not only by his responsibility for the security of the personnel, including unarmed civilians, under his control, but also out of regard for the integrity of the humanitarian and other mandates entrusted to UNPROFOR by the Security Council.’ This approach received the express support of a few states. There was, however, concern expressed about the cumbersome nature of the procedures, which, it was argued, compromised the speed of reaction to an emergency and thus the effectiveness of the use of air-power as protection for UNPROFOR and the safe areas. Moreover, the practice of the Force Commander and the Special Representative was to refuse to request such support from NATO if the attack had already ceased. This approach was also the subject of criticism. However, the way in which this delegated power is exercised is solely at the discretion of the Secretary-General or his or her designated agents. In the context of member states, as explained above, the appropriate forum for any such criticism is the Council. Nonetheless, in response to such criticism the Special Representative, with the consent of the Secretary-General, delegated the power to order the use of close air support to the Force Commander who had the express authority to delegate it to the UNPROFOR Commander. The Secretary-General summarised the position in a letter to the President of the Security Council:
In order to streamline decisionmaking within the United Nations chain of command … [a]s regards close air support to defend United Nations peace-keepers, my Special Representative has today delegated the necessary authority to the Force Commander, who is authorized to delegate it further to the Commander of the United Nations Protection Force (UNPROFOR) when operational circumstances so require.
In the context of the use of military force it is desirable that powers are delegated to the decision-maker who is most intimately informed of the facts on the ground. Accordingly, in the case of Bosnia the delegation to the UN Force Commander of the power of decision to call in close air support was a sound policy decision. There was some concern expressed that as a result of this delegation there was no UN civilian involved in the chain of UN decision-making concerning a request to NATO for close air support, and that this was not a desirable situation since it diminished political control over any action. However, such a contention does not take into account that the Force Commander is under the authority and control of the Secretary-General, and as such the Secretary-General can stipulate at any time the principles which the Force Commander must take into account when making the decision to call in military support to defend UN peace-keepers.
The Council has, however, gone beyond issues of self-defence in the case of a UN peace-keeping force when in Somalia it gave the UN Operation in Somalia (UNOSOM II) the mandate to carry out military enforcement action and it coupled this with a delegation to the Secretary-General of a power of command and control over the force. In legal terms a UN force that has had its mandate changed in such a way ceases to be a peace-keeping force, since its legal basis is no longer an implied power under Chapter VII but is an exercise by the Council of its express powers under Article 42 of the Charter to order the use of military enforcement action. This process of transformation raises issues of vires for the Council that are separate from the role of the Secretary-General. Concerning the role of the Secretary-General the issue that arises is whether as a matter of policy it is desirable for the Secretary-General to be able to order the use of force against a party to a conflict. It is not possible to give detailed consideration to this issue here, however the ordering of the use of force by the Secretary-General can only damage the perceived independence and impartiality of the Secretary-General thus hampering any future good offices or peace-keeping role that the Secretary-General may wish to play in resolving the conflict in the future. If the Council does decide that military enforcement action is necessary then it should not delegate to the Secretary-General the power to order the use of military enforcement action against a party. The Council should delegate this power to the states whose forces are carrying out the military action and give to the Secretary-General the role of ensuring that the attainment of the UN interest in the operation is achieved. The Secretary-General can fulfil this important role by conducting monitoring and supervision over the operation and by reporting and making recommendations back to the Council on a regular basis. This would strengthen the perceived legitimacy, independence, and impartiality of the Secretary-General — most importantly by the target state or states — as being the upholder of the rule of law rather than being the instrument of the use of force. This in turn can only assist any future good offices or peace-keeping role that the Secretary-General may be called upon to exercise after force has been used. This may be one of the reasons why the Security Council has no longer given command and control powers to the Secretary-General over forces carrying out military enforcement action, but has instead delegated such powers to UN member states whose forces are carrying out the operation; while entrusting the Secretary-General with the task of carrying out supervision over the action on behalf of the Council and making recommendations and reports back to the Council. By maintaining this approach the Council can ensure that there is no compromise of the unique contribution that is being made by the Secretary-General to peace-keeping in particular and to the peaceful settlement of disputes more generally.
Certain Expenses of the United Nations  ICJ Rep 151 2, 3, 9, 10, 11, 17
Crawford v Secretary-General of the United Nations 20 ILR 501 7
In Re Rosescu v International Atomic Energy Agency (1980) ILO Administrative Tribunal Judgment No 431 7
Island of Palmas Arbitration (1928) 2 RIAA 829; 4 ILR 103 4
Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) Notwithstanding Security Council Resolution 276 (1970)  ICJ Rep 16 4
Lockerbie Case (Provisional Measures)  ICJ Rep 66 4
Peynado v Secretary-General of the United Nations (1974) 47 ILR 356 7
Prosecutor v Tadic (Jurisdiction) (Appeals Chamber) (1997) 105 ILR 453 8
Reparation for Injuries Case  ICJ Rep 174 16
United Nations Charter 1945 1, 3, 4, 5, 6, 7, 9, 11, 17, 18
[*] B Comm/LL B (UNSW), LL M (Kings College London), PhD (LSE); Senior Lecturer in Public International Law, University College London, University of London. The author would like to express his great appreciation to Judge Rosalyn Higgins DBE, QC, and Dr Paul Szasz for their very helpful comments on an earlier version of this article. Any opinions expressed are, however, solely those of the author.
 The Secretary-General, in formal terms the UN Secretariat, is one of six ‘principal organs’ of the UN established by art 7(1) of the Charter. The approach of the Secretary-General constituting, for operational purposes, the Secretariat has some support: United Nations Juridical Yearbook (1982) 190; and H Kelsen, The Law of the United Nations (1951) 136.
 Consider, eg, the Secretary-General’s express power under art 99. See below nn 24–26 and corresponding text. Consider also the Secretary-General’s ‘good offices’ powers. See United Nations, Handbook on the Peaceful Settlement of Disputes (1992) 35–36; J Collier and V Lowe, The Settlement of Disputes in International Law: Institutions and Procedures (1999) 28–29; J Merrills, International Dispute Settlement (3rd ed, 1998) 226–232; and R Lavalle, ‘The “Inherent” Powers of the UN Secretary-General in the Political Sphere: A Legal Analysis’ (1990) 37 Netherlands International Law Review 22.
 On the distinction between a power and a function in the law of international institutions, see below n 19.
 On this more general role of the Secretary-General see T Franck, ‘The Secretary-General’s Role in Conflict Resolution: Past, Present and Pure Conjecture’ (1995) 6 European Journal of International Law 360, and ‘The Role and Future Prospects of the Secretary-General of the United Nations’ in D Bardonnet (ed), L'Adaptation des Structures et Methodes des Nations Unies (1986); S Schwebel, The Secretary-General of the United Nations (1952); M Virally, ‘Le Rôle Politique du Secrétaire Général des Nations Unies’ (1958) 4 Annuaire Français de Droit International 360; T Meron, ‘More Powerful Secretary-General for the United Nations’ (1972) 66 American Journal of International Law 78; P Szasz, ‘The Role of the UN Secretary-General: Some Legal Aspects’ (1991– 1992) 24 New York University Journal of International Law and Politics 161; L Gordenker, The United Nations Secretary-General and the Maintenance of Peace (1967); C Schricke, ‘L’Agenda pour La Paix de Boutros Boutros-Ghali: Analyse et Premières Rèactions’ (1992) 38 Annuaire Français de Droit International 11; T Lie, In the Cause of Peace (1954); T Boudreau, Sheathing the Sword: The United Nations Secretary-General and the Prevention of International Conflict (1991); B Rivlin and L Gordenker (eds), The Challenging Role of the United Nations Secretary-General (1993); C Alexandrowicz, ‘The Secretary-General of the United Nations’ (1962) 11 International and Comparative Law Quarterly 1109; N Elaraby, ‘The Office of the Secretary-General and the Maintenance of International Peace and Security’ (1986) 42 Revue Egyptienne du Droit International 1; J Kunz, ‘The Legal Position of the Secretary-General of the United Nations’ (1946) 40 American Journal of International Law 786; B Ramcharan, ‘The Office of the United Nations Secretary-General’ (1990) 13 Dalhousie Law Journal 742; and C Murphy, ‘The Role of the United Nations Secretary-General Since the End of the Cold War’ (1995) 35 Indian Journal of International Law 181.
 Certain Expenses of the United Nations  ICJ Rep 151, 165. See also Repertory of Practice of UN Organs, Supplement No 3, 82, 83; R Higgins, United Nations Peacekeeping 1946–1967 (1969) vol 1, 271; D Bowett, United Nations Forces (1964) 67; and B Simma (ed), The Charter of the United Nations (1994) 590–591.
 Cf however, below n 99 and corresponding text.
 Certain Expenses Case, above n 5, 166; and the opinion by the UN Legal Counsel, United Nations Juridical Yearbook (1982) 183–184.
 Certain Expenses Case, ibid 167; and R Higgins, ‘A General Assessment of United Nations Peace-keeping’ in A Cassese (ed), United Nations Peace-Keeping: Legal Essays (1978) 1, 4. The consequence of UN peace-keeping operations not being military enforcement action is that the deployment and utilisation of a force is conditional on the consent of both the states contributing troops to the force and the host state where the force is to be deployed. Certain Expenses Case, ibid 165. See also on consent: the report of the Secretary-General, A/3302 in Higgins, above n 5, 263; J Garvey, ‘United Nations Peacekeeping and Host State Consent’ (1970) 64 American Journal of International Law 241; and A Di Blase, ‘The Role of the Host State’s Consent with Regard to Non-coercive Actions by the United Nations’ in Cassese, ibid 55. This is a fundamental limitation that the Council must observe when delegating powers to the Secretary-General in the area of UN peace-keeping.
 See also Simma, above n 5, 590–591. Conforti goes further when he contends that peace-keeping is expressly provided for by art 42 of the Charter: B Conforti, The Law and Practice of the United Nations (1996) 200. But cf D Ciobanu, ‘The Power of the Security Council to Organize Peace-keeping Operations’ in Cassese, above n 8, 15. The doctrine of implied powers is well accepted under international law. See D Sarooshi, ‘The Powers of the United Nations International Criminal Tribunals’ (1998) 2 Max Planck Yearbook of United Nations Law 141, fn 7 and the citations and references therein.
 G Kirk, ‘The Enforcement of Security’ (1946) 55 Yale Law Journal 1081, 1088.
 Certain Expenses Case, above n 5, 167.
 It is generally accepted that a source of constitutional authority for the exercise of a certain power by a UN organ may be the subsequent practice of the organ. See, eg, the Namibia Case  ICJ Rep 16 ; and S Rosenne, Developments in the Law of Treaties (1994) 237.
 Judge Weeramantry in the Lockerbie Case  ICJ Rep 66, 176; J-P Cot and A Pellet (eds), La Charte des Nations Unies (1991) 645; and Simma, above n 5, 608.
 See, eg, resolutions 425 and 426 in the case of UNIFIL (Lebanon); resolutions 743, 947, and 982 in the case of UNPROFOR (former Yugoslavia); resolution 990 in the case of UNCRO (Croatia); resolution 998 in the case of the Rapid Reaction Force (part of UNPROFOR); and resolution 1037 in the case of UNTAES (Croatia). An art 39 determination does not need to refer in express terms to the article: such express references are very rare in the practice of the Council: Cot and Pellet, ibid 652. It is sufficient if the Council makes an implied art 39 determination, Cot and Pellet, ibid or if the Council recalls an earlier resolution in which it had already made an art 39 determination.
 Kelsen, above n 1, 142.
 For application of this principle to another area of international law, the acquisition of title to territory, see, eg, the Island of Palmas Case 4 ILR 103, 104.
[17 ] D Sarooshi, The United Nations and the Development of Collective Security (1999) 16–19.
 The General Assembly also possesses such a general competence to delegate powers to the Secretary-General. See Opinion of the UN Legal Counsel, United Nations Juridical Yearbook (1982) 191.
 Art 98 provides in part that the Secretary-General ‘shall perform such other functions as are entrusted to him’ by the Security Council. This provision does not, however, itself provide an express competence for the Security Council to delegate powers to the Secretary-General, since, as has been established elsewhere, there is a distinction between the delegation of a ‘power’ and the delegation of a ‘function’ under the law of international institutions such that, for our present purposes, when the Secretary-General is performing functions delegated by the Security Council under art 98 he or she is not exercising any discretionary powers but simply implementing decisions of the Council. See Sarooshi, above n 17, 10–11. The distinction lies in the degree to which real power — in other words effective decision-making power — has been transferred, ibid 10. This distinction between delegated functions (tasks) and powers has, moreover, been implicitly recognised in the context of the Secretary-General by both the UN: Repertory of Practice of UN Organs, Supplement No 1 (1958) 379 and Bowett, above n 5, 99. Cf Conforti who contends that art 98 by itself provides the basis for the delegation of powers by the Council to the Secretary-General: Conforti, above n 9, 219. Nonetheless, the Council can infer the competence to delegate its discretionary Chapter VII powers to the Secretary-General from the object and purpose of both Chapter VII and art 98 of the Charter. The object and purpose of Chapter VII is that the Council should be able to take such action as it deems necessary to maintain peace, while that of art 98 is that the other principal organs should be able to use the Secretary-General to assist in the discharge of their duties. An implied powers argument can thus be made that in those cases where the effective exercise by the Council of its Chapter VII powers requires a delegation of these powers to the Secretary-General then there is a presumption that such a delegation is lawful. On implied powers, see above n 9 and below n 89.
 On the role of subsequent practice in providing a source of constitutional authority for the exercise of a power, see above n 12. On the practice of the Council in delegating Chapter VII powers to the Secretary-General, see below Section III.
 Sarooshi, above n 17, 32–46.
 Moreover, in practice the Secretary-General may not possess the ability to carry out delegated powers due to a lack of sufficient resources being provided by the Council.
 Elaraby, above n 4, 8–9.
[24 ] S Schwebel, ‘The Origins and Development of Article 99 of the Charter’ in Justice in International Law: Selected Writings of Judge Stephen M. Schwebel (1994) 233, 238, 243; Murphy, above n 4, 183–184; and Kunz, above n 4, 790–91.
[25 ] J Lash, ‘Dag Hammarskjold’s Conception of his Office’ (1962) 16 International Organization 551, fn 39.
 The Secretary-General does not have recourse to the panoply of Chapter VII powers that the Council has in order to address the cause of the threat to, or breach of, the peace.
 See, eg, 15 UN SCOR (856th mtg) –; and below Section III.
 Peynado v Secretary-General of the United Nations, 47 ILR 356, 367–368.
 This does not mean that the Secretary-General exercising such policy decisions is always necessarily desirable, but this issue is separate from an enquiry into the legality of such an approach. On the desirability of the Secretary-General exercising delegated powers in respect of a force carrying out military enforcement action, see below n 100 and corresponding text.
 Thus, eg, the Secretary-General cannot establish a UN peace-keeping force without a delegation of power from the Council: see below n 46 and corresponding text.
 See, eg, Peynado v Secretary-General of the United Nations above n 28, 368.
 See, eg, Crawford v Secretary-General of the United Nations 20 ILR 501.
 See In Re Rosescu v International Atomic Energy Agency (1980) ILO Administrative Tribunal Judgment No 431, 8; and T Meron, ‘In Re Rosescu and the Independence of the International Civil Service’ (1981) 75 American Journal of International Law 910.
 D Hammarskjold, ‘The International Civil Servant in Law and in Fact’, Press Release, Secretary-General1035 (29 May 1961) 17. It is this independence which is the source of the perceived impartiality of the office of the Secretary-General.
 However, in practice it may be difficult for the Secretary-General not to take account of the views of member states. See B Urquhart, The United Nations and International Law (The Rede Lecture) (1985) 17. This influence by member states has seen a few commentators contend that the Secretary-General should not become involved with the carrying out of military enforcement action. See, eg, T Weiss, ‘Overcoming the Somalia Syndrome — “Operation Restore Hope?”’ (1995) 1 Global Governance 171, 177. On this issue see below also n 100 and corresponding text.
 See, eg, a rare admission in this respect made by Ceylon: 16 UN SCOR (937th mtg)  in R Higgins, United Nations Peacekeeping (vol 3, 1980) 120.
 See also J Murphy, ‘Force and Arms’ in O Schachter and C Joyner (eds), United Nations Legal Order (vol 1, 1995) 247, 249; and Conforti, above n 9, 219.
 Such reports have been used also to provide evidence more generally of the Council’s intention regarding the implementation of the terms of its resolutions. See, eg, Prosecutor v Tadic (Jurisdiction) (Appeals Chamber) 105 ILR 453, 498. A subsidiary way in which the Secretary-General interprets his or her delegated powers is to examine the amount of material resources which the Council has decided to give in order to carry out his or her delegated powers. The amount of these resources provides an important indication of the Council’s intention as to how the delegated powers should be carried out. On the interpretation of Security Council resolutions more generally, see M Wood, ‘The Interpretation of Security Council Resolutions’ (1998) 2 Max Planck Yearbook of United Nations Law 73; and also J Frowein, ‘Unilateral Interpretation of Security Council Resolutions — A Threat to Collective Security?’ in V Gőtz, P Selmer, R Wolfrum (eds), Liber Amicorum Gűnther Jaenicke — Zum 85. Geburtstag, 135 Beiträge zum Ausländischen Őffentlichen Recht und Vőlkerrecht (1998) 97.
[39 ] See the statement by Secretary-General Hammarskjold: Security Council Official Records, 888th meeting, 21 August 1960 .
 See also Bowett, above n 5, 214–15. It is, moreover, generally accepted that the Council could not be bound by the interpretation of individual members regarding a Council decision and that such an interpretation must be considered as the opinion of individual Members only. See, eg, the following statements in the Council: 2 UN SCOR (173rd mtg): Australia, 1708; Brazil, 1682–1683; former USSR, 1689–92; and UK, 1674–1675. 3 UN SCOR (390th mtg): Australia, 5–14; and China, 1–5. 4 UN SCORS (398th mtg): Belgium, 11; and USA, 3.
 G Abi-Saab, The United Nations Operation in the Congo (1978) 20.
 See the statement by Secretary-General Hammarskjold: S/4417/Add 6 in Higgins, above n 36, 132.
 Abi-Saab, above n 41, 35.
 Certain Expenses Case, above n 5, 167.
 Ibid 176–177.
 Higgins, above n 8, 7; Simma, above n 5, 592; and Abi-Saab, above n 41, 10. Thus in the aftermath of the UN-authorised military action against Iraq in 1991, the Secretary-General refused calls to establish and deploy, acting unilaterally, a peace-keeping force in Iraq to protect persecuted minorities on the basis that he lacked the constitutional authority to do so.
 N White, Keeping the Peace: The United Nations and the Maintenance of International Peace and Security (1993) 215–256.
 As the Secretary-General stated in a message to the President of the Republic of Congo: ‘Such a determination can be made only by the Security Council itself or on the basis of its explicit delegation of authority. It is of no special importance that only the Security Council can decide on the discontinuance of the [peacekeeping] operation, and that, therefore, conditions which, by their effect on the operation, would deprive it of its necessary basis, would require direct consideration by the Security Council, which obviously could not be counted upon to approve of such conditions unless it were to find that the threat to peace and security had ceased.’ S/4629, 35. Accordingly, the unilateral decision by the Secretary-General to order the withdrawal of UNEF I from Egyptian territory was ultra vires. See also, Higgins, above n 5, 271; and J Garvey, ‘United Nations Peacekeeping and Host State Consent’ (1970) 64 American Journal of International Law 241. Cf however, Di Blase, above n 8, 70–73; and N Elaraby, ‘United Nations Peacekeeping by Consent: A Case Study of the Withdrawal of the United Nations Emergency Force’ (1968) 1 New York University Journal of International Law and Politics 149.
 Thus in response to pressure on the Secretary-General to use ONUC in the Congo to carry out disarmament of certain rebel groups, the Secretary-General stated ‘this [the disarmament] cannot be done by me or the United Nations Force short of new instructions from the Security Council’. S/4629, 4.
 Cf the case of resolution 186 where the Council delegated in express terms to the Secretary-General the power to determine the size and composition of the UN Peace-Keeping Force in Cyprus (UNFICYP).
 Certain Expenses Case, above n 5, 175–177.
 See, eg, Di Blase, above n 8, 61; and Higgins, above n 5, 300.
 On art 46, see Cot and Pellet, above n 13, 732, and Simma, above n 5, 643; art 47, see Cot and Pellet, ibid 739; Simma, ibid 644.
 Certain Expenses Case, above n 5, 166.
 Thus it is that a former Secretary-General has rejected a role for the Military Staff Committee in the context of UN peace-keeping operations: B Boutros-Ghali, An Agenda for Peace (1992) 25.
 Bowett, above n 5, 357.
 See United Nations Juridical Yearbook (1990) 269.
 Moreover, in the specific case of the competence of the Security Council and General Assembly to delegate powers to the Secretary-General in respect of UN peace-keeping forces, see L Sohn, ‘The Authority of the United Nations to Establish and Maintain a Permanent United Nations Force’ (1958) 52 American Journal of International Law 229, 235–36.
 See, eg, Bowett, above n 5, 117–118.
 See ‘First Report of the Secretary-General in the Congo Crises’, S/4389, 3; and E Miller, ‘Legal Aspects of the United Nations Action in the Congo’ (1961) 55 American Journal of International Law 1, 10–11.
 The proposed ‘troika’ was to be composed of one Western, one Socialist, and one ‘non-aligned’ or ‘neutral’ member. See the statement by Krushchev, 15 UN GAOR (882nd mtg) .
 Statement by Nkrumah in the General Assembly, 23 September 1960: 15 UN GAOR (869th mtg) .
 See also K Annan, ‘Peace-keeping in Situations of Civil War’ (1994) 26 New York University Journal of International Law and Policy 623, 627; and F Seyersted, United Nations Forces (1966) 32. Cf however, the case of Somalia where there was a violation of this principle: below n 69. On UN Force Commanders, see below n 73 and corresponding text.
 See above n 8.
 See R Siekmann, National Contingents in United Nations Peace-Keeping Forces (1991) 103.
 Cf the cases of UNOSOM II (see S/25354, 3); and UNPROFOR (see S Bailey and S Daws, The Procedure of the UN Security Council (1998) 360–363).
 Many states have called for the institutionalisation of consultations by the establishment of a subsidiary organ made up of troop-contributing states. For a comprehensive account, see Bailey and Daws, ibid 362–363.
 This was a persistent and serious problem in the case of UNOSOM I and II in Somalia: ‘Comprehensive UN Report on Lessons Learned from United Nations Operation in Somalia (UNOSOM), April 1992–March 1995’, available at http://www.un.org/Depts/dpko/lessons/somalia.htm –. For description of such instances, see: S/1994/653, 28–29, 45; and J Hirsh and R Oakley, Somalia and Operation Restore Hope: Reflections on Peacemaking and Peacekeeping (1995) 119.
 Thus, eg, the Secretary-General has the power to terminate their contract of employment. This is desirable, since, as Szasz has observed, it is an essential element of the effective exercise of power by the Secretary-General that he or she be allowed to appoint and dismiss officials who are responsible to him or her in the exercise of delegated powers. Szasz, above n 4, 174, 176.
 This endorsement may have the added effect of strengthening the hand of a Special Representative in his or her dealings with the parties: see C Hume, ‘The Secretary-General’s Representatives’ (Summer–Fall, 1995) SAIS Review 81–82. Cf, however, Picco who contends that the perceived independence of UN secretariat officials from the Security Council can be of considerable importance when negotiating with parties that oppose the authority of the Council: G Picco, ‘The UN and the Use of Force: Leave the Secretary General Out of It’ (September/October 1994) Foreign Affairs 14, 16.
 NATO Doctrine for Peace-Support Operations 20 October 1993, 6.
 See ‘Summary Study of the Experience Derived from the Establishment and Operation of UNEF: Report of the Secretary-General’ (1958), contained in Higgins, above n 5, 483 .
 A result of this authority and control, as a former Secretary-General has observed, is that ‘[t]here has been an increasing tendency in recent years for the Security Council to micro-manage peace-keeping operations’. B Boutros-Ghali, Supplement to An Agenda for Peace, S/1995/1 .
 See above n 21 and corresponding text. There is the additional factor that the status of the Special Representative and Force Commander as UN Staff Members means that they are under an obligation to act solely in the interests of the Organisation. On the independence of the UN Secretariat, see above nn 34–35 and corresponding text.
 For an example of such an implied competence, see below nn 88–91 and corresponding text.
 See, eg, the delegations by the Secretary-General to the Special Representatives and Force Commanders in the cases of UNEF I (Regulation 12, UNEF I Regulations contained in Higgins, above n 5, 289); ONUC (Bowett, above n 5, 341); and UNPROFOR (below nn 86–97 and corresponding text).
 See, eg, Summary Study, above n 73 .
 On these ‘safe-areas’, see SC Res 819 and 824.
 It is clear that SC Res 836 envisaged the use of force to achieve these objectives: see, eg, the statements in the Council by the representatives of France (S/PV.3228, 13), Hungary (S/PV.3228, 52–53), and Spain (S/PV.3228, 59).
 S/25939, 2.
 Ibid 4. The ‘dual-key’ system was decided upon as the mechanism to make decisions about the use of air power and air strikes. Both the UN and NATO can initiate a call for air measures, but the other side must agree for the use of force to go ahead: each side has a veto power over the use of force.
 See above n 38 and corresponding text.
 The use of force in defence of UN peace-keepers under SC Res 836 is termed ‘close air support’ which is to be distinguished from ‘air strikes’. The Secretary-General in a letter to the Council explained this distinction: ‘Should UNPROFOR be attacked in the implementation of the plans, I would not hesitate to initiate the use of close air support without delay. To this end arrangements have been made with NATO, which has already authorized its forces to provide close air support to UNPROFOR in cases of self-defence. … a distinction exists between close air support, which involves the use of air power for purposes of self defence, and air strikes, which involves the use of air power for pre-emptive or punitive purposes. Whereas the North Atlantic Council has already authorized close air support, I have been informed by the Secretary General of NATO that NATO forces are not authorized to launch air strikes, which would require a further decision of the North Atlantic Council.’ (S/1994/94, 2.) Thus close air-support is only to be used in defence of UN peace-keepers and is distinct from air-strikes which involves military enforcement action. In the UN action in the Congo, the Secretary-General ordered self-defensive measures very similar to close air support measures taken in the former Yugoslavia when in November 1961, 13 Italian UN peace-keepers had been surrounded and were under siege by Armée nationale congolaise (ANC) troops: see Higgins, above n 36, 355.
 To ensure a quick NATO response to such a request by the UN, NATO liaison officers were stationed at UNPROFOR Headquarters in Zagreb and in Sarajevo: D Leurdijk, The United Nations and NATO in the former Yugoslavia (1994) 16.
 S/1994/300, 15.
 See above n 76 and corresponding text.
 Reparations Case  ICJ Rep 174, 182.
 It is always a feature of the use of implied powers that the organ of the organisation will in the first instance have to make a decision concerning functional necessity, thus implicitly ascertaining the existence of an implied power, and only in a very limited number of cases will this decision be subject subsequently to review by a judicial body such as that which occurred in the Expenses Case. On the competence of a UN principal organ to make such an initial determination concerning the scope of its powers under the Charter, see Certain Expenses Case, above n 5, 168.
 S/1994/300, 15.
 See, eg, the statement in the Council by the representatives of Spain S/PV.3336, 29; and Bangladesh, S/PV.3336 (Resumption 3), 217–218.
 Quote from NATO official: International Herald Tribune 26 July 1995, 6.
 Higgins states that this is a reason why ‘it may be thought [the decision-making procedures are] weighted in favour of inaction’. R Higgins, ‘The United Nations 50 Years On’ (1996) European Journal of International Law, 14.
 The Secretary-General in a report to the Council stated that incidents around and in Sarajevo in May 1995 caused the Secretary-General’s Special Representative to consider using air power. He then notes ‘the decision not to do so was criticized by some Member States’. S/1995/444, 2.
 See above n 39 and corresponding text.
 S/1995/623, 2–3.
 This position is, moreover, in accordance with the important principle of the unity of command in military operations: on this principle more generally, see Bowett, above n 5, 342; and ‘Comprehensive UN Report on Lessons Learned from United Nations Operation in Somalia (UNOSOM), April 1992–March 1995’, available at http://www.un.org/Depts/dpko/lessons/somalia.htm .
 This is precisely what the Secretary-General did in the case of the former Yugoslavia: see S/1995/444, 16–17.
 SC Res 814 authorised this expanded mandate for both the Secretary-General and UNOSOM II. This was confirmed by resolution 837, passed in response to attacks against UNOSOM II, which provides in part: ‘the Secretary-General is authorized under resolution 814 (1993) to take all necessary measures against all those responsible for the public attacks’ in order, inter alia, ‘to establish the effective authority of UNOSOM throughout Somalia’. For a description of subsequent military enforcement action by UNOSOM II, see the report of the Secretary-General: S/26022, 2–9.
 See also Picco, above n 71; and Franck, above n 4, 378–379.
 In any case the Secretary-General does not at present have the capacity to exercise such powers: B Boutros-Ghali, Supplement to An Agenda For Peace, S/1995/1 .
 For examples of cases where the Security Council has delegated its Chapter VII powers to UN member states to carry out military enforcement action and has given the Secretary-General a supervisory and reporting role as discussed in the text, see Sarooshi, above n 17, 206, 209–210, 218, 222, 237, 241, 245–246, and 264.