Jus Cogens Norms and The Historical Accident of Influential States

by Roger Alford

I know that some other international law professors are using this blog as a study aid for their public international law classes. And many of those law professors are using the Dunoff, Ratner and Wippman book, International Law: Norms, Actors, Process. So I wanted to raise a minor issue that came to mind today as I was working my way through the Cyprus material. In that section they discuss the issue of Article 53 of the Vienna Convention and treaties that are void because they violate a jus cogen norm. The specific topic concerned whether a particular treaty provision authorized Turkey to take military action to enforce the treaty, and Cyprus’s argument that it could not because to do so would violate a jus cogens norm against unlawful use of force under Article 53. Then in the notes the book identified possible candidates for jus cogen norms, including unlawful use of force, piracy, slave trading, and genocide.

Having given a fair bit of thought to jus cogens norms as of recent, it got me thinking. If jus cogens norms are higher norms of universal appeal, norms that may be thought of as part of the natural order of things, doesn’t it seem a little odd to include within that category the obligation for all non-defensive just wars to secure the approval of China and Russia?

I can’t help but think that a philosopher creating an international system from a Rawlsian original position would accept the notion of jus cogens norms. And he likely would agree that a norm like genocide or slave trading should rise to the level of a non-derogable obligation. But I rather doubt that this hypothetical philosopher would conclude that a jus cogens norm would include the obligation to secure the approval for all non-defensive just wars from a particular country that by historical accident happened to be influential at a particular moment in time, but that otherwise was not especially recognized for its wisdom, judgment, authority, or democratic legitimacy. (I’m not intending to single out any particular country when I say this). It just seems counter-intuitive to say that that country’s approval is required as part of the natural order of things and that no state can resist the obligation to secure their blessing if it wishes to wage a non-defensive just war. (I am assuming that from a philosophical perspective some wars may be just even if not waged for the purpose of self-defense, i.e., to correct a grave public evil such as the massive violation of the basic rights of whole populations).

I think I know a somewhat persuasive response to this question, but first wondered if others had any thoughts.


9 Responses

  1. Roger,

    This reminds me of Judge Higgins’s speech at the ASIL Centennial meeting, where she also expressed doubts about the jus cogens nature of the prohibition on the use of force.

    Also, when we think of jus cogens norms, we understand them as an expression of certain fundamental values, but we also see them as knowing no exceptions to their application, as being non-derogable. And that is where the prohibition on the use of force, as set out by Article 2(4) of the UN Charter, is exceptional, as it does have exceptions, namely self-defense under Article 51 and SC authorization under Chapter VII. Even if we put aside the many shady areas when it comes to self-defense, e.g. defense against non-state actors or the protection of nationals, how can the prohibition against the use of force be jus cogens if it has exceptions to it?

    But, then again, how can it NOT be jus cogens when the whole point of modern international law is to put a stop to the scourge of war, which has caused untold suffering for mankind – as the framers of the Charter would put it. And there I think lies the crux of the problem, in the conflict between idealism and realism. We have set out this incredible agenda for mankind of eradicating war, yet we know we are not able (or do not want) to realize it and so we create a legal framework built on exceptions, and we arguably even allow this framwork to be eroded by further exceptions, such as humanitarian intervention, which themselves smack of jus cogens. The only way I see for the prohibition on the use of force to be jus cogens is to say that all of the exceptions which are built into it are also jus cogens, but that, to me at least, doesn’t seem to be the most intellectually honest way to go about it.

  2. Why cannot the prohibition on the use of force be construed on the order of a prima facie obligation (after W.D. Ross)? Even Kantian ethics, following Onora O’Neill, can grant that the formal universalizability of ethical principles does not mandate uniform treatment, that principles are indeterminate and leave room for differentiated application, and that the application of principles to cases involves judgment and deliberation (for it is not on the order of a moral algorithm; cf. Allen Buchanan’s identification of at least three sources of indeterminacy with regard to the implementation of ‘abstract’ human rights). Such principles act as side-constraints, and thus while action-guiding, they do not, literally, make decisions for us. As with moral practice in general, ‘we begin by making sure that the specific acts we have in mind are not incompatible with acts on maxims of duty’ (O’Neill). Any ethic of principles theoretically must admit of the possibility of conflict between principles, so it may very well be the case that in practice one obligation will trump another (Ross would have identified this as the absolute obligation), meaning in our case we need identify the jus cogens norm that trumps the prohibition on the use of force in any given case, or perhaps identify human rights that perform this selfsame function (cf. the circumscription and changing conceptions of sovereignty in light of human rights and the prohibition against aggressive war).

    Ideally, we endeavor to follow that action which does not violate our prima facie jus cogens norms, ‘only when no such action can be found does the problem of multiple grounds of obligation arise.’ In such cases Kantian ethics does not solve any problems for us. There is nothing about the peremptory or nonderogable status of such norms that rules out the possibility of conflict between jus cogens norms, any more than in the case of Kantian ethical principles, which appear to be the closest analogue.

    We lack a plausible, let alone persuasive moral theory of international law which may be at the root of our problem here. For if it is not another jus cogens norm per se that trumps the prohibition on the use of force, a moral theory of international law might identify what values or principles are (theoretically) capable of trumping such a norm. In other words, such moral principles would modulate the application of jus cogens norms. Indeed, this is why Allen Buchanan has argued ‘that there is a need for self-conscious, systematic moral reasoning, the attempt to produce an interrelated, mutually supporting set of prescriptive principles that will provide substantial guidance for at least of the more important issues with which international law must deal or which it could profitably address.’ Buchanan himself articulates a justice-based moral theory of international law, the core of which is a normative theory of human rights. Perhaps the ambiguity, vagueness or inconsistency we identify with jus cogens norms would be addressed by a moral theory of international law. Buchanan rightly notes that contemporary political and moral philosophers have largely ignored international law. Moreover, and more to the point, ‘legal positivists make a fundamental mistake when they move from arguments against naturalism (as a position on what the law is) [keep in mind here this is in reference to the ‘naturalism’ of natural law theories] to the conclusion that moral theories of international law ought to be rejected.’ And here, again following O’Neill, I think ‘Kantian constructivism’ would be preferable to Rawlsian constructivism insofar as the former is more compatible with the spirit of international law (As Buchanan says, ‘the difficulty for Rawls…is how to distinguish between acceptable and unacceptable levels or types of force. He provides no basis for making such a distinction.’): ‘Rawls, by the time he wrote Political Liberalism, identified the reasonable with the public reason of fellow citizens in a given, bounded, democratic society. Kant was committed to establishing a conception of reasonableness or practical reason (which he too speaks of as a public reason) that would hold for any plurality of interacting beings.’ Finally, long-standing legal debates between positivist and natural law or natural law-like theories (e.g. Dworkin), as well as timeworn tensions and divisions between ‘idealism’ and ‘realism,’ lurk in the background here in a way that seems to inhibit fresh thinking or novel approaches to our subject.

    Buchanan writes that

    ‘the fundamental content of a moral theory of international law, as ideal theory, would consist of the following elements: (1) An account of the most important moral goals of the institution of international law [for Buchanan, peace and justice], (2) an articulation of the most weighty moral reasons for supporting the institution of international law as a means for achieving those goals, (3) a specification of the conditions under which the international legal system would be morally legitimate, at least in the sense of there being an adequate moral justification for individuals and groups to participate in the system’s processes of creating, applying, and enforcing rules, and (4) a statement of and justification for the most fundamental substantive norms of the system, including principles specifying the scope and limits of human rights, minority rights, and rights of self-determination and secession, principles governing the use of force on the part of states, insurgent groups, and international organizations (just war, humanitarian intervention, etc.), principles specifying criteria for recognition of entities as members of the system, and principles regulation just trade and other economic relations, the distribution of global resources, environmental protection, and international financial regimes. The needed justification of these principles would further the most important moral goals of the system and would do so in morally acceptable ways.’ (pp. 59-60)

    Buchanan admits he has not offered us ‘a comprehensive moral theory of international law,’ for instance, he does not explain how the relationship between justice, legitimacy, and self-determination applies to ‘the moral foundations of international criminal law, the rules of how war is to be conducted (jus in bello), and the morality (or otherwise) of including the right to restrict immigration among the elements of state sovereignty.’

    In agreement with the fundamental point of Professor Alford’s example, Buchanan reminds us that

    ‘the existing legal framework poses a formidable barrier to interventions, to humanitarian interventions strictly speaking. Interventions to stop horrific, large-scale violations of the most basic human rights are prohibited under international law, unless they qualify as collective self-defense or are authorized by the UN Security Council. [emphasis added] In addition, preventive humanitarian intervention—defined as intervention to prevent massive violations of basic human rights that is undertaken before violations are actually occurring or imminent—is also currently legally prohibited. Yet there can be cases—the Rwandan genocide of 1994 may be one of them—when preventive force to protect human rights, or coercive diplomacy using the credible threat of preventive force, would save many lives and do so without unacceptable moral costs.

    The NATO intervention in Kosovo (1999) is only the most recent of a series of illegal interventions for which cogent moral justifications could have been given. Others include India’s intervention in East Pakistan in response to Pakistan’s massive human rights violations there (1971), Vietnam’s war against Pol Pot’s regime of mass killings in Cambodia (1978), and Tanzania’s overthrow of Idi Amin’s murderous rule in Uganda (1979). [….] In all four instances the intervention was, according to the preponderance of international legal opinion, a violation of international law. None was a case of self-defense and none enjoyed UN Security Council authorization.’ (Buchanan, pp. 443-444)

    Readers can for examine and assess for themselves Buchanan’s proposal for improving the international law of humanitarian intervention.


    Onora O’Neill, ‘Kantian Ethics,’ in Peter Singer, ed., A Companion to Ethics (Cambridge, MA: Blackwell, 1993), pp. 175-185;

    Onora O’Neill, ‘Constructivism in Rawls and Kant,’ in Samuel Freeman, ed., The Cambridge Companion to Rawls (Cambridge, UK: Cambridge University Press, 2003), pp. 347-367; and

    Allen Buchanan, Justice, Legitimacy, and Self-Determination: Moral Foundations for International Law (New York: Oxford University Press, 2004).

  3. Please eliminate the first ‘for’ in the last sentence above.

  4. Professor Alford,

    You do in fact single out some countries (contrary to the parenthetical note), namely Russia and China, which is fine by me, but thought I should mention it.

    Moreover, I’m a tad curious as to why you limit yourself to a ‘non-defensive just war,’ rather than speaking to principles of humanitarian intervention in general.

    Lastly, in addition to Buchanan’s proposal for implementing the principles of humanitarian intervention within the international community (which, technically speaking, is illegal inasmuch as it violates existing UN-based law on humanitarian intervention), readers may want to compare other discussions and proposals on the ethics and legality of humanitarian intervention:

    Chatterjee, Deen K. and Don E. Scheid, eds. Ethics and Foreign Intervention (Cambridge, UK: Cambridge University Press, 2003).

    Holzgrefe, J.L. and Robert O. Keohane, eds. Humanitarian Intervention: Ethical, Legal, and Political Dilemmas (Cambridge, UK: Cambridge University Press, 2003).

    Jokic, Aleksander, ed. Humanitarian Intervention: Moral and Philosophical Issues (Orchard Park, NY: Broadview Press, 2003).

    And I’m preparing myself for any future post on the moral justification of the war in Iraq based on an invocation of some such principles of humanitarian intervention. 😉

  5. The reason I used “non-defensive just war” instead of “humanitarian intervention” is I wanted to speak in more philosophical terms rather than legal terms. Humanitarian intervention is becoming a term of art for a particular kind of war. It is possible I suppose that some just wars may be for purposes other than self-defense or humanitarian intervention, i.e., the kinds of wars that a well-functioning Security Council might authorize in a perfect world to secure and maintain international peace and security.

  6. I appreciate the explanation/clarification.

    Admittedly I’m not a legal scholar or practioner and could be mistaken, but my reading of the aforementioned literature does not at all suggest that ‘humanitarian intervention is becoming a term of art for a particular kind of war,’ and thus wars to ‘secure and maintain international peace and security’ could still fall under that heading (while for Buchanan, ‘a well-functioning Security Council’ would have to consist solely of ‘democratic, human rights-respecting states’!). Moreover, ‘humanitarian intervention’ is broader than ‘non-defensive just war’ insofar as it conceives of interventions to ‘secure and maintain peace and security’ as possibly entailing actions that don’t amount to war (e.g., mere presence of armed forces or exercise of police powers).

  7. Dear Professor Alford,

    Your post and the clarifications in the comments section raise a number of issues.

    A first issue relates to the ius cogens nature of the prohibition on the use of force in international relations, in particular because of the exceptions that exist. Can we classify the prohibition on the use of force as a ius cogens norm while recognizing at the same time that exceptions on this prohibition exist? This question has also been raised in Mr. Milanovic’s comment on your post. Contrary to Mr. Milanovic, and for reasons that are set out at the end of this comment, I see no problem why the built-in exceptions to the use of force could not be ius cogens themselves without being intellectually dishonest. Yet, I think we should be clear about what these exceptions are. For the moment, I’ll stick to the exceptions that are recognized by the UN Charter itself, i.e. Security Council authorization and self-defence.

    Since your question deals with “non-defensive” just wars, we can leave the discussion of self-defence under art. 51 UN Charter aside and focus on the use of force authorized by the UN Security Council. In this respect, I believe your post raises the point of the composition of the UN Security Council, and the selection of its Permanent Members in particular. You can take this question to its most extreme point and ask why Security Council authorization is needed at all. The answer to this goes to the heart of the UN international security system. I don’t think that your post wishes to go this far and hence, there is probably no need to go into it. The problem you raise is more that the current Security Council’s composition is an accident of history rather than an accurate representation of the most important and influential states in the world at the beginning of the 21st century. Imagine for a moment that the Security Council reflected more accurately the international community with no veto power for any of its members; would your question still be the same? In other words, would you in such a situation accept that individual states need to seek Security Council authorisation before waging a non-defensive just war, or would you object to this authorisation as such and grant all states the right to decide for themselves?

    This brings me to the third question that is indirectly raised by your post. Should we expand the exceptions to the prohibition on the use of force to other “non-defensive” just wars? As you describe in the comments section, these non-defensive just wars would include just wars for “purposes other than self-defence or humanitarian intervention, the kinds of wars that a well-functioning Security Council might authorize in a perfect world to secure and maintain international peace and security.” I must say that I find this statement a wee bit surprising! On the one hand you cite a Security Council authorization as a novelty, while, on the other hand, you accept humanitarian intervention as an established exception to the prohibition on the use of force. I would think that it is rather the other way around! But then, the statement confirms that the current composition of the Security Council is at the core of your problem and that you would have fewer/no issues with a “well-functioning” Security Council. As to the exception of humanitarian intervention, I agree that it is becoming a term of art, but then, what’s in a name? One of the reasons why the discussion about humanitarian intervention is so difficult is that there is no uniform definition of it. Interventions for humanitarian reasons come in different varieties and shapes: non-forcible assistance, intervention by invitation, intervention authorized by treaty or the Security Council, intervention for the protection of your own nationals, intervention to stop human rights violations or to prompt a regime change. Moreover, they can be conducted unilaterally or multilaterally. Some authors would classify all these interventions as “humanitarian intervention”, while others reserve this for purely unilateral interventions. In my opinion, it is definitely debatable that all of these types – and in particular unilateral interventions – have achieved the status of exception to the prohibition on the use of force. Although I agree that certain types of intervention (e.g. intervention by invitation, intervention to protect own nationals) are now recognized as exceptions to the prohibition on the use of force, I do not think that international law in its current state allows individual states to unilaterally wage a non-defensive war, however just it may be.

    Maybe the key to your question is that the prohibition on the use of force is not as absolute as it would seem at first hand, but that it is only in specific situations (for example, the unilateral non-defensive use of force without the Security Council’s authorization) that the prohibition is of ius cogens nature. Contrary to Mr. Milanovic, I do not think a narrowly tailored rule is intellectually dishonest. The fact that no derogation is permitted from a rule of ius cogens does not automatically imply that the rule must be absolute with no scope for exceptions. Ian Brownlie (p. 489, 6th edition) quotes the International Law Commission’s Commentary on the draft on the law of treaties on the meaning of “derogation” as implying that states cannot contract out of a ius cogens rule, either formally or through acquiescence. The definition of “ius cogens” does not impose rigidity, but even allows for evolution as long as the new rule is of the same character as the rule it is overriding. If we want to have a workable ius cogens norm on the use of force, what we need is a clear understanding of what is permissible and which procedures need to be followed to allow the use of force. A norm that is framed only in absolute terms, without attention to nuances, will not lead us very far. Not only will it fail hopelessly to give us any indications in real life situations, but its rigidity will also render it useless when it has to be balanced against other norms of equal standing, such as the rules on genocide.

  8. Annabel,

    Re your remark on derogation, states can contract out of the prohibition on the use of force, in a way – I’m of course talking about intervention by invitation, which you also mentioned. A state can say to another state, ok, I need your military forces, please do come in. The problem in these cases is not the jus cogens nature of the rule, but the validity of the consent – e.g. as in the US intervention in Grenada. On the other hand, a state cannot validly give consent to another state committing genocide or torturing its people.

    I agree that, in principle, a rule which is not absolute but has certain narrowly tailored exceptions might be called a jus cogens one. However, the prohibition on the use of force is not such a rule, and the exceptions to it are not only not narrowly tailored, but multiply like mushrooms. The problem is not even the level of enforcement, but the normative framework itself – I concede that if we did have a perfect Security Council the situation might be different, but we don’t, and we don’t by design.

    I think humanitarian intervention is a very good example, actually. You could say with virtual certainty that this was not a recognized exception to the prohibition on the use of force up to the end of the Cold War. Now, after the interventions on behalf of the Kurds in Northen Iraq, after Kosovo, I think you can make a decent case that it is, and I say this as one whose city has been bombed during one. If the US intervened in Rwanda, or intervened now in Darfur, we could say that this would be morally right but legally wrong, or we could, as Prof. Cassese did in his article in the EJIL, say that ex injuria oritur jus. I’d go for the former, but I don’t deny the possibility of the latter.

    My point is that the whole area of the use of force is laddened with such conceptual uncertainties that it is actually pointless to say that the rule is jus cogens. I just don’t see what’s the value added, when we are not prepared as a global society to give the underlying values the normative clarity they need.

  9. Marko

    I agree that general statements of the kind ‘the prohibition on the use of force is ius cogens’ lack normative clarity, but the answer that I tried to suggest in my comment is that maybe we should narrowly tailor the ius cogens prohibition, which is different from narrowly tailoring the exceptions.

    In your first comment you very accurately pointed to the tension between idealism and realism. Somewhat surprisingly for myself, I find myself arguing for a dose of realism here! “Ius cogens” is a very peculiar category under international law and I think it would benefit from a “hygienic” approach to it. A clear but limited rule would in that respect be better than a rule that is too overbroad and vague. My concern is that if we are too generous with the term “ius cogens” we risk undermining its value for international law. Therefore, it is my opinion that we don’t need to throw the baby out with the bathwater and claim that the prohibition on the use of force can never be “ius cogens”. At the risk of simplification, I’d like to draw this parallel: we don’t consider murder as a violation of “ius cogens”, but murder with a genocidal intent is.

    Narrowly tailoring the ius cogens prohibition of course does not imply that all the other instances of use of force suddenly become permissible. A state wishing to use force, will still have to deal with its obligations under treaty and customary law on this matter. Hence, the tension that Professor Alford raised in his post between the “ius cogens” nature of the prohibition on the use of force and the need to obtain security council approval for non-defensive wars is not that clear to me. This approval is required regardless of the qualification of the rule as ius cogens. The true issue becomes the composition and the functioning of the Security Council and its legitimacy for the international community.

    Although it’s less related to Professor Alford’s original question, I would also like to add that a narrowly tailored ius cogens norm will better enable us to deal with conflicts between different “ius cogens” norms. “Intervention by invitation” is a case in point. You could see it as a derogation on the use of force as in your last comment, or you could see it as a conflict between the prohibition on the use of force and the principle of self-determination. A narrowly tailored rule on the use of force should accomodate for the requirements of the principle of self-determination. One rule of “ius cogens” can modify another, the question becomes which one should prevail. I tend towards self-determination. The validity of the consent becomes an issue then, and so does the question of whether the reasons for the “invitation” were valid under international law. If a state is calling for help in its lawful exercise of force within its territory, other states can respond to this call for assistance, which is in accordance with the demand of sovereignty and self-determination. Contrary to this, it is clear that a state cannot lawfully commit genocide on its territory. The rules against genocide here prevail over self-determination. Since the reasons for the invitation were illegal, another state would be barred from legally intervening by invitation.

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