Dr Gleider I. Hernández is lecturer in law at the University of Durham; Thomas R. Liefländer is a PhD candidate at the University of Cologne.
The recent events rapidly unfolding in Libya have raised a number of important questions for international lawyers. Among them, the precise delineation of the scope of Security Council authorisation to use force has given rise to intense discussions on this blog (see here, here, and here). To recall, the Security Council authorised the use of “all necessary means” in order to protect civilians and civilian-populated areas as regards the situation in Libya (in Security Council Resolution 1973). The discussion on this blog centred primarily on exactly how narrowly the relevant authorisations are to be construed, focussing in particular on how direct the relation must be between any given action and the protection of civilians or civilian-populated areas.
Against this background, we intend to use the Libya situation to analyse a different question, namely, the possible legal consequences of exceeding the scope of Security Council authorisation. We approach the issue from two related, but nevertheless distinct, angles. First, we consider whether, given Security Council authorisation to use “all necessary means” in Libya, it is still possible that international military actions exceed the scope of that authorisation, thus triggering Libya’s right to self-defence. This issue of overstepping authorisation takes on renewed urgency in the light of NATO’s admission that it has killed civilians in certain air raids (most notably the air raid of 22 June 2011, reported in the Guardian, where NATO was bombing checkpoints that were not military installations—see infra for further discussion) and France’s controversial decision to supply the Libyan rebels with arms (see this Guardian article, as well as Dapo Akande’s recent post).
Secondly, we will offer some brief thoughts on whether the leaders of the States acting under Security Council authorisation may be committing the crime of aggression, as defined for the purposes of the Rome Statute of the ICC, by overstepping their mandate. The second question is, of course, entirely hypothetical, considering that the ICC’s jurisdiction over the crime of aggression cannot be activated before 2017, and that the existence of such a crime under customary international law is in any event doubtful. Nevertheless, we believe this line of enquiry to be important, as a device to highlight the grave consequences that may result from an overly broad reading of a Security Council authorisation.
The General Framework
Are there circumstances in which a State may invoke its right to self-defence to resist military action taken against it pursuant to a Security Council authorisation? Does international law allow such a target State to use force against those States acting under such authorisation?
Perhaps unsurprisingly, one finds little scholarly writing on these questions. It may appear irrelevant; after all, it seems completely counterintuitive for international lawyers to consider that a State might be allowed to use force to resist acts that have been authorised by the Security Council. Yet the question should not be disposed of too quickly, since a military campaign such as that of NATO against Libya, whether or not authorised, clearly reaches the threshold of force usually required for an “armed attack” in the factual sense to be present.
Nevertheless, there would appear to be at least three avenues by which the right of self-defence of the targeted State can be denied. First, Security Council-authorised action, cloaked as it is with a presumption of legality, does not constitute an “armed attack” in the legal sense of the Charter, thus never triggering the right to self-defence contained in Article 51 in the first place. Secondly, the right to self-defence under Article 51 is excluded by the Security Council’s prerogative. If even the lawfully exercised right to self-defence under Article 51 only exists until the Security Council has taken those measures necessary to restore international peace and security, it follows logically that any use of force against measures serving this very purpose is automatically excluded. Finally, responding to authorised military measures with self-defence would appear to constitute a breach of the obligation to abide by Security Council decisions under Article 25 of the Charter; the right to self-defence can hardly be read as allowing the target State to obstruct measures intended to enforce the relevant Security Council decision.
As a counterargument to all these approaches, one could argue that the Charter has not superseded the underlying inherent right to self-defence under customary international law; however, even if the customary right exists in parallel to Article 51 of the Charter, the target State nevertheless remains bound by the limitations established by the Charter, and in particular to the supremacy clause found in Article 103. For our purposes, the difference between the two rules is thus immaterial.
Accordingly, as a general rule, the right to self-defence is not available as a legal response to military enforcement authorised by the Security Council. However, it would be overly hasty simply to end our analysis here, especially given the renewed academic scrutiny of the legality of Security Council action under the United Nations Charter (see, e.g., Antonios Tzanakopoulos’ monograph Disobeying the Security Council, and the resulting book discussion on this blog). Study has generally focused on the external legality of the Security Council’s actions, and the consequences of a finding of the illegality thereof. Yet, to our mind, surely the reverse side of the coin is the legality of actions taken in pursuance of the Security Council’s act, a form of “internal legality”. By “internal legality” we mean the legality of acts performed under the aegis of the Security Council’s acts, in essence querying their conformity with the Security Council’s decision, as they are acts in pursuance of powers delegated thereby.
It is with this concern in mind that we now turn to the possible consequences at international law, including the possibility of a target State invoking self-defence, in response to actions purportedly undertaken in pursuance of a given Security Council resolution, but deemed to fall outside the scope of that resolution.
Whatever the evidentiary difficulties inherent in making such a claim (see infra), our analysis proceeds on the assumption that there exist situations where a State has acted outside the scope of relevant Security Council authorisation. In the Libya situation, such instances might arise in the form of military action taken by Nato, in territory still held by Gaddafi’s forces, that did not pursue the direct aim of protecting civilians or civilian populated areas. Such action would not be covered under the unusually restrictive terms of operative clause 4 of Resolution 1973, and ipso facto, not be authorised under the Charter. Our position is that the direct consequence of such a finding would be that the use of force in this particular instance breached Article 2(4) of the Charter and was thus illegal.
To use an example drawn from the unfolding Libya situation, a claim has been advanced that Nato have carried out raids on checkpoints in the towns of Khoms and Nalut in western Libya (as reported in the Guardian). If confirmed, this report suggests that Nato has now moved beyond targeting military installations and armour, which raises questions as to how such operations may validly be reconciled with clause 4 of Resolution 1973, considering that the targeted checkpoints would not appear to be a direct threat to civilians or civilian-populated areas.
Assuming it is possible for acts undertaken in pursuance of a Security Council resolution to fall outside its scope—any other conclusion would render the limitations in operative clause 4 meaningless—the question now depends on whether the threshold of an “armed attack” would be reached. Presuming the threshold rules are the same irrespective of Security Council authorisation, only force used outside the scope of authorisation would be relevant in assessing whether that threshold has been reached; but if such force were deemed to constitute an armed attack, we contend that the right to self-defence would be triggered.
Importantly, this assessment would not seem to change when the excessive force is being used by a collective entity such as Nato rather than a single State; it is simply unconscionable to suggest that a State could be stripped of its right to self-defence if a group of other States have attacked it illegally whilst hiding behind the veil of the separate legal personality of the international organisation.
Of course, any force used in self-defence by a State in response to acts falling outside the scope of a Security Council resolution would have to comply with the regularly required proportionality requirements of Article 51 of the Charter, as well as with the applicable rules of the ius in bello. In assessing what is proportionate in the former sense, one would again have to limit oneself to taking into account only those instances of force used that have overstepped the relevant authorisation.
All the above considerations hinge upon on whether one can validly conclude that a State has overstepped the scope of a given Security Council authorisation, which is a difficult proposition to establish, especially if the authorisation is phrased in vague terms. Any imprecision in the drafting of the resolution becomes crucial when we are dealing with self-defence. In this respect, paragraph 94 of the ICJ’s Advisory Opinion in respect of Kosovo, which lays out a more contextual mode of interpretation for Security Council resolutions, may be a welcome aid, but does not necessarily make the interpretation in casu any easier. The controversy surrounding France’s airdrop of weapons demonstrates that the interpretation of Resolution 1973 is anything but a settled matter; this apparently includes divergent opinions between two States that not only were involved in passing Resolution 1973, but have also acted as joint leaders in giving effect to it (see the Guardian, reporting the UK’s convoluted position on the weapons air drop by France).
Presumably, a State wishing to invoke its right to self-defence must discharge a high burden, proving both that a given act (or acts) taken against it both fall outside the scope of authorisation given by the Security Council and that it rises to the level of an “armed attack”. First, it would have to dispel claims of good-faith factual error (see e.g. Nato’s “weapons system failure” after a failed air raid, reported in the Guardian, which caused at least nine civilian deaths). Secondly, it would have to contest a characterisation of certain installations as targets falling within the scope of the authorisation (see, e.g., Nato’s bombing of a residential compound purportedly used as “an important command and control centre”, which led to the deaths of fifteen individuals, including three children, reported in the Guardian). Thirdly, the target State may have to overcome claims of good-faith legal error. This relates to whether a State is permitted to rely on its own legal interpretation of an instrument, or whether an objective standard may be used. However, as there is generally no such thing as an “error of law” defence in international law, we do not consider that a target State would in principle be barred from invoking self-defence simply because the acting State itself considers all its acts to fall under the authorisation.
This last consideration relates to problems connected to international law’s reliance on auto-interpretation. States acting in pursuance of a Security Council authorisation will invariably claim that the totality of their acts were conducted under its aegis and thus not susceptible of triggering the target State’s right to self-defence; the target State will, whenever possible, use whatever ambiguity is possible to assert a legal entitlement to self-defence. In this regard, even if in practice most target States resist force used against them, any lack of clarity in a Security Council resolution allows States on both sides to defend their arguments through legal language, a non-negligible point when their argument is to justify the use of force, with all the attendant consequences thereof.
The Crime of Aggression
The definition of the crime of aggression agreed on in Kampala by the ICC States Parties criminalised “the planning, preparation, initiation or execution, by a person in a position effectively to exercise control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations.” Extensively commented upon in 2010 on this blog (see here, here, and here), we seek to rely on this definition to address one question, purely as an intellectual exercise: could the use of military force pursuant to, but potentially going beyond, a Security Council authorisation, fall under this definition?
The understandings attached to the definition of the crime of aggression make it clear “that in establishing whether an act of aggression constitutes a manifest violation of the Charter of the United Nations, the three components of character, gravity and scale must be sufficient to justify a ‘manifest’ determination”. Whereas gravity and scale do not pose great conceptual problems, the notion of character is difficult to grasp.
When would the use of force exceeding Security Council authorisation be of such a character as to justify its classification as a “manifest violation of the Charter”? It would seem that action taken in pursuance of a particular mandate, but going slightly beyond what is allowed in order to reach the goals of the mandate, could not be so characterised. By way of a crude analogy to administrative law, this may qualify as a “simple” rather than a “manifest” violation. On the other hand, a State leader using Security Council authorisation as a pretext to pursue other aims not covered by the mandate (i.e. regime change in the guise of the protection of civilians), and systematically exceeding the scope of authorisation, could eventually attract the ICC Prosecutor’s attention.
The threshold for falling under the definition of the crime of aggression would certainly be higher when the Security Council’s authorisation is drafted using ambiguous terms, where various reasonable interpretations are possible. To violate the Charter “manifestly” in such circumstances would particularly turn on which interpretation one adopts. Presumably, actions taken in keeping with a reasonable interpretation would not be judged as “manifestly” violating the Charter. Yet, what constitutes a “reasonable” interpretation of the relevant Security Council resolutions will fall to the ICC’s various chambers to determine, as only their assessment is relevant in a prosecution before it. This raises certain problems that place the crime of aggression squarely outside the framework of public international law. For example, considering that “error of law” – including when based on professional advice – is not a defence to the crime of aggression (cf. Article 32(2) of the ICC Statute), it cannot be excluded that a leader could be indicted under the ICC’s definition of aggression simply for adopting a “wide” interpretation of the authorisation that the relevant chamber eventually judges as “unreasonable”. The implications of this are, to put it mildly, staggering.
The difficult legal questions that will invariably be raised in any assessment of whether a particular action exceeded the scope of the Security Council’s authorisation make it doubtful that anything but a limpid, unambiguous case could ever satisfy the “manifest” threshold. Yet, as it remains to be seen how the ICC Prosecutor and chambers would – if they ever will – interpret and apply that definition, the possibility of ICC action could serve as a warning to any leader acting under Security Council authorisation against adopting an excessively permissive interpretation of that resolution or any limitations on the mandate contained therein.
This post served primarily to develop some ideas about the possible consequences of a finding that military actions have exceeded the scope of what has been authorised. We have concluded that force used by States that oversteps such authorisation may activate a target State’s right to self-defence. The likelihood of such a scenario arising is higher whenever the authorisation is framed in imprecise terms. Furthermore, a leader authorising such force may commit the crime of aggression, as defined under the ICC Statute.
These potentially grave consequences of overstepping an authorisation call for two things, which echo what Jules Lobel and Michael Ratner  urged already in 1999. First, the Security Council should always attempt to phrase its authorisations to use force as clearly as possible, leaving as little room as possible for divergent interpretation. Secondly, ambiguous authorisations should be narrowly construed by States acting under the Security Council’s mandate. Going beyond such pragmatic solutions, the question raised taps into the interface between theory and practice: it is all fine and well to raise questions of auto-interpretation, and to quibble over whose interpretation is more authoritative and why; but in the heat of conflict, especially in the highly sensitive field of international military action, and with the severe consequences that can result from error or merely from diverging interpretations of the same instrument (both of which may be legitimately founded), a call for caution is surely warranted.
 As the ICJ established in the merits phase of Nicaragua, pp. 119-120, para. 231, it is possible for force (in that case, transborder incursions) to be used against a State in such a manner as to fall below the threshold of an “armed attack”.
 This may well be the essence of claims that the military action in Libya (and Côte d’Ivoire) were directed at regime change, rather than protecting civilians.
 Jules Lobel and Michael Ratner, ‘Bypassing the Security Council: Ambiguous Authorization to Use Force, Cease-Fires and the Iraqi Inspection Regime’ 93 AJIL 124 (1999).