Security Council Resolutions as Evidence of Customary International Law

In 2012 the International Law Commission began to address one of the last major uncodified areas of public international law: how norms of customary law (CIL) are to be identified.  The exercise at the ILC has not been an easy one.  States commenting in 2016 on the Commission’s “draft conclusions” expressed concerns on a variety of issues.  One of the most contentious was the role of international organizations (IOs) in the creation of custom.

The topic has been the subject of academic conferences at the University of Manchester, the University of Michigan and elsewhere, as well as a growing volume of law review commentary (see here, here, here, here and here).  And in early January, the United States submitted comments on the draft conclusions that were, to put it mildly, opposed to any role for IOs.  Closer to home, Kristen Boon, Isaac Jenkins and I have just published an article on the role of the Security Council in generating evidence of custom related to non-international armed conflicts (NIACs), an area of intense Council involvement. In this post I’ll describe the ILC’s view of IOs, the United States’ response, and then our affirmative arguments specific to the Security Council.

The ILC addresses IOs’ role in generating custom in two of its draft conclusions.  First, Conclusion 4(2) on the “Requirement of Practice” provides, “In certain cases, the practice of international organizations also contributes to the formation, or expression, of rules of customary international law” (p 76).  Second, Conclusion 12 addresses “Resolutions of International Organizations and International Conferences”:

1. A resolution adopted by an international organization or at an intergovernmental conference cannot, of itself, create a rule of customary international law.
2. A resolution adopted by an international organization or at an intergovernmental conference may provide evidence for establishing the existence and content of a rule of customary international law, or contribute to its development.
3. A provision in a resolution adopted by an international organization or at an intergovernmental conference may reflect a rule of customary international law if it is established that the provision corresponds to a general practice that is accepted as law (opinio juris) (p. 78).

On their face, these provisions represent a modest relaxation of the traditionally state-centric nature of CIL.  But ambiguities abound.  Article 4’s statement that “in certain cases” IO practice may contribute to CIL provides no detail on the circumstances in which that might happen.  Article 12 is a bit more specific, focusing on IO resolutions, but in saying only that such resolutions “may provide evidence for establishing the existence and content of” CIL, it provides no guidance on when or how that might occur.   Nor does either provision address how IO practice of any sort might embody either or both of the two traditional elements of CIL, practice and opinio juris.

Adding to this ambiguity is the ILC’s extraordinarily limited notion of when an IO acts in its own legal capacity for purposes of contributing to CIL, as opposed to merely serving as a forum in which its member states express their own views.  The Commission states in commentary that this should occur most clearly “where member States have transferred exclusive competences to the international organization.”  (p. 89).  The sole example given is the European Union and it is difficult to think of others.   IOs may also act on their own behalf when member states “have conferred powers upon the international organization that are functionally equivalent to the powers exercised by States.” (id.). An example of those actions is IO secretariats serving as treaty depositories.  (id).  Acts not functionally equivalent to those of states “are unlikely to be relevant practice.” (id.). This last category would seem to encompass most IO actions.

The ILC underlines this exceptionally narrow view of IO corporate action in a comment on the “certain circumstances” language in Conclusion 2: “References in the draft conclusions and commentaries to the practice of States should thus be read as including, in those cases where it is relevant, the practice of international organizations.”  (p. 88). Most IO practice, in other words, is actually state practice.

The ILC’s narrow approach continues when it discusses the United Nations, the IO most frequently cited as a source of custom.  While one might imagine UN organs with specific competences having a role in generating evidence of custom in those areas, the ILC commentary discusses only resolutions of the General Assembly (p 107).   Readers are left to wonder whether this is because, in the Commission’s view, only the GA can contribute to custom by virtue of it being “a plenary organ of near universal participation,” (id.) or whether it is just the best example among many others.  The most obvious explanation is that the ICJ has cited almost exclusively to GA resolutions when invoking IO practice in cases such as Congo/Uganda (¶168), Nicaragua (¶195) and the Nuclear Weapons Advisory Opinion (¶70).

But even this narrow view of IOs’ role in CIL was unacceptable to the United States.  In comments submitted to the Commission on January 5, the US ruled out any role for IOs: “It is axiomatic that customary international law results from the general and consistent practice of States followed by them out of a sense of legal obligation.” (p. 2; emphasis in original). The US argued “there is no support” for the “some circumstances” language in Conclusion 4(2) and proposed that the section be deleted entirely. (p. 5).  Following on this position, the US described IO resolutions (the subject of draft conclusion 12) as embodying “the opinio juris of States, although potentially also their practice.” (p. 17).

Perhaps anticipating that this categorical position would not carry the day in the Commission, the US went on argue that even if one accepted a role for IOs in CIL, Conclusion 4(2) and accompanying commentary is vague and question-begging in ways that mirror many of the problems noted above (pp. 3-5).  These objections are thought-provoking are deserve serious consideration, even if one supports an IO role in custom.

The proposal that Kristen, Isaac and I make, however, rests on several facts and legal propositions neither side in this debate has raised.  We argue that the Security Council regularly and consistently imposes obligations on parties to NIACs that differ in important ways from otherwise applicable international law or, in some cases, from one side in a dispute over the content of a particular customary norm.  We created a dataset of all Security Council resolutions on the most significant NIACs from 1990-2013 and coded them for the imposition of binding obligations on a range of international law issues.

Two findings from the data stand out.  First, the Council has been omnipresent in contemporary NIACs, passing at least one resolution on 76% of all NIACs from 1990 to 2013, increasing to 80% for NIACs that began after 1990.  Second, the Council imposed obligations that are highly relevant to several unresolved CIL debates.  In particular, our data show that the Council required non-state actors (usually armed rebel groups) to respect human rights in 68% of NIACs in which it had invoked Chapter VII and in 83% of such conflicts that commenced after 1990.  Similarly, the Council ordered non-state parties to abide by NIAC peace agreements in 83% of conflicts with such agreements, and in 92% of such conflicts in which it invoked Chapter VII.   We argue these findings are evidence of CIL with regard to whether non-state parties are bound by human rights obligations and whether peace agreements ending NIACs are legally binding.  Both issues are highly contested and the addition of Council practice could well sway the debates.

From a theoretical perspective, we argue that when the Council imposes such obligations it acts as an agent for all UN member states.  Article 24(1) of the Charter provides that member states “confer on the Security Council primary responsibility for the maintenance of international peace and security, and agree that in carrying out its duties under this responsibility the Security Council acts on their behalf.”   (emphasis added).   The Special Court for Sierra Leone relied on an Article 24(1) agency theory to hold that an agreement between Sierra Leone and the UN was, as a result of Council approval, “an agreement between all members of the United Nations and Sierra Leone.” (Prosecutor v. Taylor, Case No. SCSL-2003-01-I, Decision on Immunity from Jurisdiction, ¶38 (May 31, 2004) (emphasis in original).

Does the agency theory mean that member states have delegated to the Council a capacity to contribute to CIL?  In its ILC submission, the US argued emphatically not: the mandates of IOs are “carefully negotiated treaties” that “rarely, if ever” provide an express authorization “that the organization exercise the powers of member States to generate practice for purposes of customary international law.” (p. 4).  This was obviously true when the UN Charter was negotiated.  But the US position seems anachronistic today.  Consider the consequences of states having delegated to the Council authority to address an extraordinary range of legal questions arising from NIACs – and having done so for more than 25 years — but withholding any CIL consequences of that delegation.   Those consequence – i.e. evidence of custom — would not be attributable the Council.  But neither would they be attributable to the member states, who would have delegated the authority to act to the Council, effectively disengaging those acts from their (state-based) customary law implications.  Member states cannot claim ownership of acts they have delegated to the Council.  The acts would thus disappear into a legal black hole.  An entire realm of rich international practice in responding to and remediating NIACs would be lost to CIL.

Second, the post-Cold War Council has developed a set of legal tools to address NIACs that no state possesses individually.  It can impose obligations on non-state rebel groups.  Under Charter Article 2(7) it can address NIAC issues normally within a state’s domestic jurisdiction. And it can legitimize or delegitimize the use of force by some or all NIAC parties.  Council acts pursuant to these exclusive powers cannot be attributed to member states.

Third, our data show a Council involved in almost all contemporary NIACs.  The Council has addressed NIACs in every year, in every region, of varying duration, of varying number of actors, of varying battle deaths and civilian casualties, at various points in the conflicts, and both inside and outside the spheres of influence of every hegemonic state.  No state or group of states comes close to matching this breadth of practice.  The nature of Council involvement is also remarkably deep, ranging from simply imposing obligations to dispatching peacekeeping missions to imposing sanctions.  To take sanctions as an example, only four of the sixteen Council sanctions regimes in place in 2017 targeted state actors exclusively; the rest targeted non-state actors exclusively or both state and non-state actors.   Obviously, no state or group of states has addressed NIACS more broadly or more comprehensively.

In sum, the Council has exercised unique Charter to powers to intervene in extraordinarily intrusive ways into the most severe NIACs of the post-Cold War era.  It has done so using authority specifically delegated by all member states.  And in its interventions, the Council has consistently imposed the same obligations on NIAC parties for over two decades, despite wide variations in the causes, location, severity and duration of the conflicts.

This is not to say the case for considering Council practice as evidence of custom is an easy one.   Many other objections can be raised, most of which we address in our article.  Circling back to the US objections outlined above, we believe our views are potentially consistent with its position that while an IO can never contribute to custom on its own behalf, IO resolutions can be evidence of state practice.   If UN member states have enlisted the Council as their agent to address legal issues in NIACs, then Council practice is ultimately state practice, since member states are the principals in the principal-agent relationship.   The US omits discussion of the agency provision of Charter Article 24(1), perhaps because it, like the ILC, is focused almost exclusively on the General Assembly.   But our view would admit Council practice to the mix of evidence relevant to custom while not radically departing from the fundamentally statist conception of CIL the US advances.