Home Armed Conflict The Genesis of Lex Specialis

The Genesis of Lex Specialis

Published on April 30, 2014        Author: 

When it comes to describing the relationship between human rights and international humanitarian law, the lex specialis principle is frequently taken for granted, as if it has somehow always been there, carved in stone. But what is its actual genesis? By ‘genesis’ I do not mean its ancient history. Yes, it was in the Digest of Justinian. But, honestly, who cares? We have little or no idea of what exactly the lawyers of the Roman and Byzantine empires meant by the expression and how they applied it in practice, and indeed there are several different ways of conceptualizing lex specialis.

My question is rather this: when did we, the community of international lawyers, start using this language to describe the relationship between IHL and IHRL? The timeframe for answering that question is necessarily more limited and easier to manage, since IHRL did not become a part of public international law until after the Second World War. I am obviously too young to have direct experience of this, but my impression has been that during the first fifty years or so of their co-existence very little thought was given to how IHL and IHRL would interact, and when the issue was discussed it was generally not framed in terms of lex specialis. My hypothesis is thus that the term entered common parlance among the international lawyers who have dealt with the issue only after the end of the Cold War, and specifically only after the ICJ’s 1996 Nuclear Weapons advisory opinion, para. 25, when the Court itself first used the term:

In principle, the right not arbitrarily to be deprived of one’s life applies also in hostilities. The test of what is an arbitrary deprivation of life, however, then falls to be determined by the applicable lex specialis, namely, the law applicable in armed conflict which is designed to regulate the conduct of hostilities. Thus whether a particular loss of life, through the use of a certain weapon in warfare, is to be considered an arbitrary deprivation of life contrary to Article 6 of the Covenant, can only be decided by reference to the law applicable in armed conflict and not deduced from the terms of the Covenant itself.

To prove or disprove this hypothesis, which is what I am doing in a paper I’m writing right now, I need to do two things. First, I need to establish how the Court itself got the idea to use the lex specialis principle to describe the relationship between the rules of IHL and IHRL. Was it complete innovation on its part? Did it come from the pleadings of some of the participants in the advisory proceedings? Or did it come from generally accepted scholarship on the issue? Second, I need to look at the scholarship itself, specifically those works that examined the issue before the Nuclear Weapons opinion and immediately after it.

The pre-1996 scholarship I will leave aside for the purpose of this post, but from what I’ve read so far there are few, if any references to the lex specialis principle as a solution to normative conflicts between IHL and IHRL (I will obviously very much appreciate it if readers could point me to any such references in scholarship in whatever language). But I’ve read through all of the pleadings in the two nuclear weapons cases (the WHO and GA requests), both written and oral. And out of the 40 or so states that appeared before the Court in the two cases, do you know how many referred to the lex specialis principle? Just one – the United Kingdom.

In the first round of the WHO case the UK did not even discuss the human rights issue. When it came to the second round of written pleadings, which were due at the same time as the first round of pleadings for the General Assembly Nuclear Weapons case, the UK decided to give its comments on the submissions in the WHO case in its written statement in Nuclear Weapons, i.e. that single document was both the second submission in the WHO case and the first in Nuclear Weapons. The UK now did extensively discuss human rights and environmental law, arguing that the issue was not the compatibility of nuclear weapons with these legal regimes in abstracto, but ‘whether any of the rules of the law of human rights or the law on environmental protection can be construed, in accordance with the general principles stated above, as prohibiting the use or threat of use of nuclear weapons when carried out by way of legitimate self-defence.’ (WS, para. 3.98 (emphasis in original)).

In that regard, the UK noted that Article 15(2) ECHR explicitly referred to derogations from the right to life for deaths resulting from lawful acts of war, and argued that:

Although the International Covenant on Civil and Political Rights contains no provision equivalent to Article 15(2) of the European Convention, Article 6(1) prohibits only the ‘arbitrary’ deprivation of life. If the Covenant is applicable at all to the taking of life in the context of an armed conflict, it is necessary to determine what the term ‘arbitrary’ means in that context. Since the taking of life is an inescapable feature of the conduct of armed conflict and since it has never seriously been suggested that the Covenant outlaws the use of force by way of national self-defence, the reference to ‘arbitrary’ deprivation of life must contain the means for distinguishing between those acts of taking life in armed conflict which are compatible with Article 6 of the Covenant and those which are not. The only sensible construction which can be placed on the term ‘arbitrary’ in this context is that it refers to whether or not the deliberate taking of life is unlawful under that part of international law which was specifically designed to regulate the conduct of hostilities, that is the laws of armed conflict. On that basis, the use of a weapon to take life in armed conflict could only amount to an arbitrary deprivation of life, for the purposes of Article 6 of the Covenant, if it was contrary to the laws of armed conflict but not otherwise.

(WS, para. 3.101)

After briefly looking at the travaux of the Covenant and the work of the Human Rights Committee, the UK concluded its submissions on human rights as follows:

The protection given by the law of human rights does nor, therefore, lead to a different conclusion regarding the legality of the use of nuclear weapons from that provided by the law of armed conflict. Since the law of human rights is concerned primarily with the protection of human rights in peacetime, whereas the law of armed conflict is a lex specialis designed to regulate the conduct of hostilities, it is entirely appropriate that the human rights agreements should, in effect, refer to the law of armed conflict in order to determine whether or not any particular instance of the deprivation of life in wartime is arbitrary. The same principle applies, a fortiori, in respect of the protection of other human rights.

(WS, para. 3.108)

This, then, was the very first appearance of lex specialis in the written pleadings, and indeed the only such appearance in the UK’s written statement. Notably, neither of the paragraphs I have just quoted in full provide any references or citations to authority of any kind. The UK’s counsel obviously did their job well, since the language of the UK’s submissions is clearly reflected in paragraph 25 of the Court’s Nuclear Weapons opinion. This is, to my mind, undoubtedly the intellectual genesis of the Court’s holding. In the combined oral hearings in the two cases no state, not even the UK,  nor France,  nor the United States, nor Russia, mentioned lex specialis, although the UK did articulate a version thereof without the Latin: CR 1995/34, at 43-44.

So why is this relevant? I do not want to go here into the merits or demerits of lex specialis and its various different conceptions. My only point is this: despite the Latin veneer of antiquity, and whatever its merits, the lex specialis principle was NOT part of mainstream thinking on the relationship between IHL and IHRL before the 1996 opinion (assuming there was any mainstream thinking on this issue in the first place). If it was, one would have expected more than one, single, isolated and conclusory reference to the principle in the hundreds of pages of written and oral pleadings before the ICJ.

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21 Responses

  1. Paola Gaeta

    Dear Marco, thanks for this excellent post. I see now from where the idea that IHL is a sort of “separate regime” comes from….the UK assertion, reflected in part in the ICJ advisory opinion, is however wrong since the principle of lex specialis is a principle that regulates the apparent conflict between two applicable rules. As the UK counsel put it, ie that HRL regulates peacetime and IHL regulates wartime, then the issue of conflict does not arise at all and there is no need to disturb the lex specialis principle. However, if the two bodies of law and their rules are applicable, one has to adopt a case by case approach to see if there is a conflict between the applicable IHL rule and the applicable HRL rule. And here the principle of lex specialis might come into play, together with other regulatory principles, such as that of lex posterior…..I look forward to reading your paper that I am sure will be brilliant, as all the papers you write. Best, Paola.

  2. Marko,

    Some excellent legal archeology, but where does it leave us? As you mention, little thougth was given to the relationship between IHL and IHRL in the first fifty years of their co-existence. Could the fact that the lex specialis argument originates in the Nuclear Weapons proceedings not be explained by the fact that this was the first instance where (more) serious thought was given to the relationship between IHRL and IHL? In which case the relative novelty of the lex specialis argument is neither here nor there? Looking forward to the full article!


  3. Dear Marco,
    It’s an interesting question. It was something I just touched in my paper “The Universal Declaration of Human Rights and Armed Conflicts: From Fragmentation to Complexity”, Anuário Brasileiro de Direito Internacional, Vol. 2, pp. 48-67, 2009 []. I look forward to reading your paper!
    Best, Xavier

  4. Marty Lederman

    Marko: As you know, in the Nuclear Weapons opinion the notion of “lex specialis” is not used to suggest that IHRL is *displaced* — the controversial notion advanced by the U.S. during the Bush Administration — but instead merely to guide interpretation of what “arbitrary” ought to mean in a particular context. (Although I don’t know much of the origins of that adjective in the IHRL treaties, this basic interpretive move seems intuitively right to me–of course what is “arbitrary” in one context will not be “arbitrary” in another, and it’s difficult to see how a use of force can be “arbitrary” if it is done in compliance with traditional, well-established legal norms developed for the particular context. It may be many other things, but “arbitrary” isn’t one of them.)

    Even if the NW opinion is the source of *that* use of “lex specialis,” isn’t the source of the “displacement” notion the more interesting, the more important, historical question? (I vaguely recall that you go over most of this in your Norm Conflicts piece — apologies in advance if I’m covering old ground.)

  5. Marko Milanovic Marko Milanovic

    Many thanks for everyone for their comments.

    Aurel, just briefly in response, it’s my point exactly that little serious thought was given to the IHL/IHRL relationship before 1996. What I object to is the idea that lex specialis has somehow always been there, that it’s obvious, a matter of ‘legal logic,’ the ‘traditional approach’, rooted in custom, etc.

    Marty, I agree completely! There’s nothing wrong with reading ‘arbitrary’ in Article 6 ICCPR in line with IHL – but you don’t need to refer to some lex specialis principle to do this. Indeed, virtually all states participating in the Nuclear Weapons proceedings agreed that IHL was relevant for interpreting Article 6, whether it was Russia or the US (which argues that nuclear weapons were lawful) or their opponents (e.g. in most detail the Solomon Islands). Moreover this is simply in line with Art. 31(3)(c) VCLT.

    But there’s a further step here, which is that the UK for instance argued that human rights add nothing, i.e. that ‘arbitrary’ in wartime necessarily and in all circumstances equals IHL, which is non-obvious, at least. And this purely interpretative, weak version of lex specialis is of no help with say Arts. 2 and 5 ECHR, which do not contain the arbitrariness standard. (Indeed, all states who dealt with human rights in the advisory proceedings relied on the Art. 15 ECHR derogation clause to deal with this problem).

    You are completely right that the total displacement version of lex specialis is different. The actual ‘lex specialis’ language stems from Nuclear Weapons, that much is clear. But the substance has much longer roots – it’s actually a reference to the classical, pre-WWII categorical distinction between the law of war and the law of peace. But again, in the NW proceedings no state (not even the US) clearly argued that the ICCPR cannot as such apply in wartime. The closest you get to that is an off-hand remark in one of the pleadings by Russia that human rights operate in an entirely different dimension.

  6. Marty Lederman

    Thanks, Marko. Well, if that’s the case — that “virtually all states participating in the Nuclear Weapons proceedings agreed that IHL was relevant for interpreting Article 6” — then the origins of *that* idea must go back much further. Then again, perhaps it’s an uncontroversial idea, and one that doesn’t warrant an elaborate historical inquiry. The interesting question, if there is one, is how the stray (and probably unhelpful) label of “lex specialis” the NW opinion thereafter transmogrified into the displacement notion. Or perhaps that’s not very important, either, since now virtually no one (?) argues that IHL entirely displaces IHRL (as opposed to informing its application).

    All of which is to say that in writing your paper, it might help to establish clearly, right at the outset, which *idea* (which argument) is the subject of your inquiry. Of course, the use (and misuse) of the “lex specialis” label might be a significant element of your narrative — it might explain the slippage from an uncontroversial claim to a much stronger and less justifiable one — but isn’t it the origins of the substantive argument, rather than of the nomenclature, the more pertinent focus of the historical inquiry?

  7. Marko Milanovic Marko Milanovic

    Marty, let me qualify my previous remark somewhat: all states participating in the NW proceedings that actually addressed the human rights issue in any detail agreed that IHL (as well as the jus ad bellum for that matter) were relevant for interpreting the arbitrariness standard. But that was a small minority of the total number of participating states, and it was clear that the arguments were made up more or less on the spot. There was no significant background to it.

    The transmogrification of the lex specialis label into the total displacement theory really happened only under the Bush administration, as far as I can see, and moderated as the time went on. One other clear proponent of the thesis that I can recall was Russia in the Georgia v. Russia No. 2 case before the ECtHR – see Georgia v. Russia (II) (dec.), App. No. 38263/08, 13 December 2011, para. 69: Russia described as arguing that ‘the Convention did not apply to a situation of international armed conflict where a State Party’s forces were engaged in national defence, including in respect of any required operations abroad. In such circumstances the conduct of the State Party’s forces was governed exclusively by international humanitarian law.’

    The Court declared the application admissible, and the case is now pending.

  8. Yakob Levi

    Excellent post! I have to confess, however, that I’m always a bit puzzled by this forced wedding between IHRL and IHL. HRL deals with the relationship between individuals and the state whereas HL deals with the relationship between certain groups of individuals (armed forces, civilians, etc.) and hostile armed forces.
    If I’m Carthaginian or live in Carthage, it is the state of Carthage that needs to ensure that my human rights are respected. If Rome invades Carthage, it is the Roman army that needs to respect humanitarian law and, quite frankly, there is little that Carthage can do about it.

  9. Jordan

    It is unrealistic to pretend that human rights did not exist prior to WWII, or even prior to WWI. Blunschli famously wrote that human rights apply during war and he preferred that human rights have primacy over ordinary treaties. For evidence of the rich history of human rights, especially in the Americas and Western Europe from the 1700s to the 1980s, see, e.g., Paust, International Law as Law of the United States chpt.5 (2 ed. 2003) (Carolina Academic Press — or the article in 10 Mich. J. Int’l L. 543-652 (1989) which formed much of the basis for the chpater. For the fact that human rights law applies during war, see, e.g., Paust, Bassiouni, et al. International Criminal Law cpt. 8 (4 ed. 2013) (Carolina Academic Press). For the reach of human rights to various non-state actors, see, e.g., id.; and the article at (also demonstrating that international law has never been merely state-to-state).
    With respect to lex specialis, one should recall that the Latin phrase appears in no known international legal instrument, especially in no known human rights or law of war instrument. Further, the claim by some that human rights law should be displaced during armed conflict (like the Bush-Cheney regime — ) has no support in treaty law or customary international law based on general patterns of practice and general patterns of opinio juris. It is a nonsense claim, especially in view of the fact that Article 103 of the U.N. Charter requires that a member’s human rights obligations, which apply universally and in all social contexts, prevail over those in any ordinary treaty (like law of war treaties) and that norms jus cogens, including several human rights, will necessarily trump inconsistent laws of war. See, e.g., (also demonstrating why U.N. troops are bound by human rights law).

  10. Thanks Marko for a fascinating post – you may already know this, but there was rather an intense discussion in the EHRAC team (Phil Leach, Kirill Koroteev and me) representing the applicants in the first six Chechen cases at Strasbourg (Isaeva etc, judgments of 24 February 2005) prior to the oral hearing as to whether we should refer to IHL given that was clearly an internal armed conflict – and as Paola pointed out in an earlier article the Russian Constitutional Court held in 1995 that IHL applied in the First Chechen War. We decided not to, and that was plainly the correct decision – see William Abresch’s 2005 article – and the judgments stick to article 2 ECHR. I’m also your neighbour (pp.485-498) in v.14 n.3 (2009) Journal of Conflict and Security Law discussing some of the same points. You might be interested – I can send you a copy – in the judgment by District Judge Workman in RF v Zakaev in 2003, when he held that there was an armed conflict in Chechnya 1994-7, so that the crime of murder could not be committed, under the specialty rule.

  11. Jordan

    p.s. Yakob: in addition to the above re: the fact that international law has never been merely state-to-state and that human rights duties have been applied re: non-state actors [1701992], see also re: the latter (human rights obligations of private companies and corporations)

  12. Yakob Levi

    Dear Jordan, my puzzlement was not about HR obligations of private actors, it was about mixing HRL and HL. Human rights can and should be ensured by the state even in time of war (eg. right of access to court, religious freedom, right to vote, etc.). Humanitarian law is to be respected by enemy armed forces in a particular context, that of armed conflict. I have to say that I also share some puzzlement about private parties having human rights obligations and consider it a bit of a neo-colonialist attitude, but that has nothing to do with this post.

  13. Jordan

    Yakob, as noted in 1701992, the fiction that international law was ever state-to-state (and that corporations had no duties) was “colonialist,” unreal, and always opposed.

  14. Jordan

    p.s., I meant, of course, ever merely state-to-state.

  15. Ezequiel Heffes

    Marko, thanks for this insightful post. I’m also looking forward to reading your paper!

    Generally, the only issue I can find regarding the non-existence of the lex specialis maxim before 1996 is related to certain human rights treaties that preclude their application in times of armed conflict. Even though they do not mention that expression, their drafters may had been thinking on that.

    Although it is only for IACs, this could be the case of the Inter-American Convention on Forced Disappearance (1994), Art. XV, which affirms that it “shall not apply to the international armed conflicts governed by the 1949 Geneva Conventions and its Protocol concerning protection of wounded, sick, and shipwrecked members of the armed forces; and prisoners of war and civilians in time of war”. A similar situation could be analyzed in the International Convention Against the Taking of Hostages (1979) where it is recognized that everyone has the right to life, liberty and security of person, as set out in the Universal Declaration and the ICCPR. There it is affirmed that the treaty “shall not apply to an act of hostage-taking committed in the course of armed conflicts as defined in the Geneva Conventions of 1949 and the Protocols thereto, including armed conflicts mentioned in article 1, paragraph 4, of Additional Protocol I of 1977”. It seems to me that these treaties are lex generalis and IHL lex specialis.

  16. Julia

    Did you see that the High Court have discussed lex specialis in their decision yesterday Mohammed v. Ministry of Defence (QBD) as a doctrine to distinguish conflicts between HRL and IHL?

  17. Marko Milanovic Marko Milanovic


    I think the two treaties you mention draw on the whole debate regarding the definition of terrorism and terrorist acts, specifically in the context of (often very messy) wars of national liberation. A number of these treaties exclude their applicability in armed conflict. I don’t see any particular use in using the lex specialis/generalis labels in such circumstances. Whatever the worth of that principle, it is really usable only in the absence of any explicit provision in the treaties regulating normative conflict between them.


    Yes, I did see the judgment, which is very interesting. I’ll be writing up a post on it later today. Thanks!

  18. Julia

    I look forward to your post on Mohammed v. MOD as it has some bearing on an assessment I am currently researching. Thank you!

  19. Juan A. Yanez-Barnuevo

    Thanks to Marko and to the other contributors to this interesting discussion.
    I have the impression that the debate is a little bit constrained by the reference specifically to the concept of “lex specialis” and mainly to decisions and pleadings in the ICJ (and other international courts).
    If we open the scope of the discussion, I think we would discover that indeed there was a discussion about the relationship between IHRL and IHL well before the Nuclear Weapons advisory proceedings.
    In fact, my recollection is that the UNGA started to discuss the question of the protection of human rights in situations of armed conflict back in 1968 and following years, as a consequence of the Arab/Israeli war of 1967 and the Israeli occupation of Arab territories (I was then a delegate of Spain to the Sixth – Legal – Committee). The concern felt by the ICRC as to such “invasion” of its traditional turf led, on the one hand, to hot debates in the UNGA on the proper ambit of its discussions and recommendations (there were quite a few) and, on the other, to the Geneva Diplomatic Conference in 1977 which adopted the Additional Protocols I and II to the Geneva Conventions of 1949.(By the way, I was also involved in that process).
    So in fact there was already a realization in the international community that there was an interrelation (and perhaps areas of conflict) between “Geneva (and Hague) law” and “New York law” at least since the late 60s. A different thing is how the debate was framed and whether the idea of “lex specialis” was expressed somehow since that time (under that label or not).

  20. Jordan

    Juan: Bluntschli was around long before there was a United Nations.

  21. Great blog, interesting discussion. Though I struggle to see how the relationship between IHRL and IHL can be conceptualised in terms of lex specialis in the sense IHL would necessarily prevail over IHRL. Contrary to some perceptions, IHRL does apply to conflict situations, subject to provisions on derogation (eg Art 4 ICCPR – but some rights are inderogable, including the right to life) and/or to the way provisions on ‘progressive realisation’ ‘to the maximum of available resources’ (Art 2 ICESCR), are applied. The case mentioned in the blog illustrates that both IHRL and IHL apply, even though one can inform the interpretation of the other. In case of interest a 2003 FAO publication on the right to food in emergencies discussed some of these issues:
    Best, Lorenzo