Recent events in Syria –President Bashar al-Assad’s horrific chemical weapons attack on civilians in Idlib, and the Trump administration’s subsequent missile strikes – have again forced to the fore the debate over the legality of humanitarian intervention in international law. Naturally, we tend to focus on these questions in the context of an immediate catastrophe, or a particular use or threatened use of force. Thus, the legal question of humanitarian intervention is often inextricably bound up with the extent to which any particular military operation is sound policy. That focus may over-emphasize action, and fail to grapple sufficiently with the wide space in which states do not act, or limit policy options based, at least in part, on the constraints imposed by international law. I would like, therefore, to try to separate for a moment the legal question from President Donald Trump’s recent actions, and from our sense of the extent to which he may be able to put forward a responsible strategy in Syria. To be clear, I have little hope that this president is the one who will be able to thread this needle. But, as we are all painfully aware, Syria’s humanitarian disaster is hardly new. For years now, international law has failed in Syria.
The international law question at stake is simply this: May a state or states lawfully use force against another sovereign state for purely humanitarian reasons, without sanction by the UN Security Council? A humanitarian intervention exception to the UN Charter’s Article 2(4) prohibition on force has some compelling advocates, most prominent among them, Harold Koh, former Legal Adviser to the State Department. On the other end of the spectrum are those who find most if not all U.S. exercises of force more destructive than beneficial. For that latter group, the legal question is not fraught; the formalist Charter prohibition on force simply aligns with their policy preferences. Yet my informal read is that a large group of international law scholars fall somewhere in the middle. Many in this group take the view that military force for humanitarian purposes without Security Council authorization would be unlawful. But their devotion to international law and the Charter prohibition on force is in tension with their urgent hope – at times even a sense of moral imperative – to take action in the face of horrific humanitarian tragedy and, frankly, evil. They are sympathetic to the Koh position, even as many refuse to accept it as lex lata, the law as it exists today.
Among this group of international lawyers, I see two primary approaches to negotiating this tension: (1) the “purist” hard constraint approach; and (2) the “legitimate but unlawful” approach, represented best by the U.S. posture in Kosovo, in which the U.S. government (along with many NATO allies) decided not to present a legal justification for the intervention.
And then, of course, there are those who advocate a third approach: to divine or craft a narrow exception to the Charter prohibition, using the Koh test or other proposals. I do not intend to weigh all of these proposals here; but I am writing to defend the effort. I see this third way as perhaps – counter-intuitively – the only means of preserving international law’s credibility in the use of force realm.
Those in the first, “hard constraint,” category quite reasonably read the UN Charter as unequivocally prohibiting the use of force against other states in all circumstances except those spelled out in the Charter itself. Essentially, these exceptions are: in self-defense in response to an armed attack, or with the sanction of the UN Security Council. For this group, military intervention for purely humanitarian reasons can be lawful only when accompanied by a UN Security Council Resolution. Yet the UN Security Council will never authorize force when one of the five permanent members (who each hold a veto) is complicit in the atrocities in question. Taking this legal logic to its inevitable conclusion, this group, at times regretfully, asserts that – even in cases where it may be the best option as a matter of policy – states must categorically take force off the table as unlawful.
The second, “legitimate but unlawful,” group finds this categorical rule untenable. It advocates that, in certain extraordinary circumstances, states should act without crafting a legal justification. This was the approach in Kosovo, where the U.S. government and NATO put forward factors that explained the action but not a legal justification. In the Kosovo context, the theory was that, by not offering a legal justification, the U.S. government might limit the precedential effect of its acts. Some now advocate this approach in the case of Syria. (Indeed thus far we have yet to see a clear legal justification from the Trump administration for the recent strikes.) The reasoning behind this proposed approach varies. For some, this may come down to a simple descriptive recognition that states may – and have – acted in contravention of this rule, and yet they, as lawyers, do not see a plausible legal defense. For others, this approach may be an acknowledgement of their own personal tension between wanting the state to act and wanting to preserve the sanctity of international law, which they believe prohibits action even during humanitarian crises.
These first two approaches – the purist/hard constraint approach and the Kosovo approach – broadly capture the two categories of concerns that international lawyers raise in criticizing the concept of a humanitarian exception to 2(4).
The purist, doctrinal concern is simply that the treaty is clear, and that no interpretive flexibility or subsequent customary evolution can change the Charter rule. The second is a policy concern, that crafting an exception to 2(4) will erode the norm, leading to abuse and ultimately to the failure of the whole international legal system. This is the slippery slope concern. I have come to think that these concerns rest on faulty grounds: The first, purist approach is not fully representative of how international law functions in practice; and the second “Kosovo” approach is more likely to erode 2(4) and international law more broadly than would crafting a limited exception for humanitarian intervention.
As I have mentioned, there have been many proposals for how to read a humanitarian exception into 2(4), and I will not address them all here. I do want to address certain premises inherent in the above positions that I think are faulty. The first is the view that custom can never change a treaty. That may be a traditional view, and yet it is not necessarily reflective of how states actually interact with treaty obligations. In fact, there are areas where treaty expectations do in fact change with time and with the subsequent practice and acceptance of states. As but one example, the ICRC has recognized in its updated Commentary to the 1949 Geneva Conventions the changing expectations among states vis-à-vis those obligations (including that some treaty rules may have fallen into desuetude). The recognition that treaty rules may evolve through implicit acceptance by states is at odds with the formalist rule that treaty obligations can change only through formal amendment.
Second, it is worth pausing to point out that when national security concerns are at stake, the U.S. government has taken an extremely aggressive approach to virtually all aspects of its interpretation of its authority to use force. And over time, our allies and many international lawyers have become comfortable stretching the outer bounds of what international law has historically been thought to permit in this space. The concept of what constitutes an “imminent” attack has been massaged to include years of advance notice on potential terrorist attacks, and the slow march toward nuclear capability. Self-defense-justified infringements on state sovereignty have made room for a state’s unwillingness or inability to address non-state actor threats from within. (And of course, the U.S. government’s legal standard for who may be targeted and detained within an armed conflict has expanded to include a whole supporting cast of characters, though the extent to which the U.S. positions have found purchase with other states is unclear.) States will continue to stretch the law to adapt to changing security risks; must they remain purists only when humanitarian intervention is at stake?
And finally, that brings us to the slippery slope concern. Many have argued that any attempt to craft a humanitarian exception to the UN Charter risks seriously degrading, if not taking down, the whole international legal order. But there is no neutral position that does not also contain this risk. The prohibition on force may be eroding with or without international lawyers crafting a humanitarian exception. And states may seek to abuse international law – and the exceptions already explicitly contained in the Charter – whether or not international lawyers recognize the reality of states’ needs to take humanitarian action. Surely the law cannot account for every extraordinary moment of moral necessity. But we are far past being able to argue that humanitarian catastrophe and the need for intervention are too rare to require shaping the law to address them. If, instead, we international lawyers faced with this tension ask states to disregard international law because it fails to meet our sense of what is legitimate and – moreover – what may be our moral imperative, we risk eroding these legal rules. And if we constrain ourselves repeatedly out of respect for the law, and thus fail to take actions that may prevent unthinkable horrors, we may cause others to believe – indeed we may come to believe ourselves – that the international legal order is failing us.
The reality is that there will be times that states use force out of a sense of moral imperative and long-term strategic importance, and not out of a specific self-defense rationale. International law – and we international lawyers – can try to stand in the way, at times constraining morally imperative action, at times getting bulldozed; or we can look the other way and be sidelined, perhaps even tell policymakers and our clients to move forward without us. Or, we can engage and work with them to help craft the most sound, narrow, acceptable grounds possible, together with our allies. This view is not an acceptance that international law does not matter. It is an acceptance that international law – like so much public law – operates in a dynamic space that is inevitably interwoven with the reality of how states act and the widespread acceptance of its legitimacy.
It bears recognizing that states are having their own conversations while we international lawyers debate the legality of humanitarian intervention. Many, if not most, international lawyers take the view that non-UN-sanctioned force in this context would be unlawful. Among states, by contrast, there has been widespread support for military action in response to humanitarian crises. Nevertheless, few have put forward an actual legal justification, with the significant exception of the UK in 2013. The only way to ensure international law’s continued relevance is for it to keep up.
None of this answers the “what now” question for the U.S. in Syria. The (i) broader legal justification for humanitarian intervention should not be confused with whether any particular policy action is (ii) wise or (iii) well implemented. Those are three critical and complex inquiries. (And of course, even explicitly authorized UN-sanctioned efforts can go awry.) Most of us contemplating the legality of intervention are lawyers. Policy is not our core competence, though our instincts and policy preferences necessarily inflect our legal analyses. I do not know the answer on Syria. I am not sure that anyone does, though it is worth recognizing the many officials and policymakers from across the spectrum of politics and places in government – career diplomats, military officials, former Secretaries of State – as well as among our allies, who have advocated taking stronger action against Assad.
Now, I must address the very large elephant in the room. I do not think anyone with national security or foreign policy experience genuinely thinks President Donald Trump is the right person to navigate these complexities. But this is not the first time the legality of humanitarian intervention is on the table, and it will not be the last time. And with respect to Syria alone, the fact that international law may have played a role in taking intervention off the table during the Obama presidency (and there are subtle indications that it did) should weigh heavily on us now. Or perhaps the role of international law in those deliberations was negligible, and for the future of international law, at least, that should be no less a concern.