an international and interdisciplinary journal of postmodern cultural sound, text and image

 Volume 11, April - September 2014, ISSN 1552-5112



H.L.A. Hart on International Law


Anthony H. Lesser

Facebook Twitter Google Digg Reddit LinkedIn Pinterest StumbleUpon Email


In chapter 10 of The Concept of Law, Hart (1994) considers whether International Law is genuinely law or is better seen as international morality, and argues that it is indeed law, though differing in some important respects from municipal law. This chapter is of more than purely historical interest, but has been discussed less than most of Hart’s work.  There is, though, a recent excellent article by Mehrdad Payandeh (2010). My conclusions are indeed similar to those of Dr. Payandeh, and to those of Jeremy Waldron, but there are further issues regarding the details of Hart’s argument and the practical consequences of what he says which I will go into in this article.


 The issue of whether international law is truly law has been discussed by many writers since Hart; and few, if any, deny that international law is law. Even Goldsmith and Posner (2005) do not make this claim, but maintain rather that, though it is law, there are considerable limits to what it can accomplish, there is no automatic moral requirement of states to obey it, and in practice, states obey it only when it is in their interest to do so. All these points, if one substitutes “individuals” for “states”, could be, and have been, made with regard to municipal law; which no one denies, is law.


Nevertheless, it remains instructive to consider why the arguments that international law is not law do not succeed, and what the arguments are for asserting that it is law. A critical examination of Hart’s arguments has relevance both for the theoretical understanding of law and for practical political concerns: this is true both of those of his arguments that remain valid and those which on examination prove to be inadequate.  It is important to note that Hart’s argument was concerned with international law in its current form. If international law were to become more widely accepted in practice as well as theory, and more enforceable and systematic (as some recent writers on just war theory, such as Rodin (2002) and Fabre (2011) have argued that it could and should) then some of the considerations that Hart raises might no longer apply. But it will, at best, be some time before this happens.


We need to begin by considering Hart’s account of the methods one should use in order to decide whether something is or is not law. As in his work as a whole, he used ideas found in contemporary work at Oxford and elsewhere, notably J.L. Austin’s ‘ordinary language philosophy’, found particularly in papers such as ‘A plea for excuses’ (1961), and Winch’s The Idea of a Social Science (1958).  From Winch, Hart took the view that to understand what people do, you must understand how they themselves see what they are doing. Hence to understand law, you must understand how people living under a legal system view the law. In adapting Winch’s theory to jurisprudence, Hart added the idea that it is of special importance to understand how law is understood by those who administer it, though one must certainly also consider how it is understood by those who live under it.


 From Austin, Hart took the analogous but not identical idea that in order to elucidate a concept, such as law, one must as a first move understand how the term, or terms, referring to that concept are actually used, i.e. when, according to usage, it is correct to call something ‘law’ and when it is not. Hart followed Austin, rather than Winch, in holding that this is only a first move: one must understand existing usage and the theory that it presupposes, but it may still be possible to improve on it, theoretically or practically. Thus about international law, Hart says that he will not dismiss the doubts about whether it is ‘really’ law with ‘a simple reminder of the existing usage’ (p.214),  i.e. the fact that it is standardly called law, because we have to consider whether this usage ‘is likely to obstruct any practical or theoretical aim’ (ibid.).


 Hart also maintains that international law differs from a legal system as described in the earlier part of his book. The book argues that a developed, ‘non-primitive’ legal system consists of the union of primary rules, which require, or forbid, types of behaviour, and secondary rules, which determine how primary rules are to be created, changed and applied. The secondary rules must include an ultimate, or basic, rule of recognition, defining the sources of law in that system, e.g. statute, precedent and custom, and what criteria must be satisfied if a law or rule is to be valid. But Hart says that this is an elucidation rather than a definition of law (p.213); and it is a further question whether systems, or sets, of rules which do not meet these criteria should still be regarded as law, or indeed, as Hart reminds us on the same page, whether systems which do meet them but are radically unjust should be regarded as valid legal systems. So for Hart we begin by noting that international law is called law; we then have to consider the objections to this, and the force of these objections, and in the light of this to decide whether our practical and theoretical aims are best served by retaining existing usage or by changing it.


Of the two standard objections to calling international law ‘law’, Hart rejects one altogether, and develops the other along lines suggested by his own theory. The objection he rejects is the argument that international states, while being sovereign, cannot be legally bound. This objection can take two different forms, only one of which is fully considered by Hart, though they are both worth at least brief consideration. First, it may be held that it is logically impossible for a sovereign state to be legally bound in any way. This, as Hart notes, though with regard to the less strong version of the theory, which he himself considers (see below), is both unsupported by any argument and also contrary to the observed facts. States clearly do enter into relationships defined by treaties, and consider themselves bound by those treaties. There is a question whether these bonds are legal or moral; but this cannot be settled a priori, with no reason being given as to why they should be moral rather than legal, especially when those who enter into them consider them to be legally binding.


In reply to this, it might be held that whenever a state binds itself, its sovereignty is thereby limited, so that by definition it ceases to be sovereign. This is a possible way of defining sovereignty, but not a useful one. It would have the consequence that in practice there are no sovereign states, since all states do limit themselves in this way by treaties. Also, it would have the consequence that it is better for a state to be non-sovereign than to be sovereign, since many treaties are beneficial for all the parties concerned. Finally, the consequence for international law would be that, admittedly, it does not apply to sovereign states: but it would apply to all actual states, since on this definition none of them are sovereign. So the argument that international law cannot be law, because it is logically impossible for a sovereign state to be legally limited, fails either way. On one definition of sovereignty this assertion is simply false, because sovereign states do limit themselves legally. On another definition it is true, but the consequence is that no actual states are sovereign, so that it does not follow that international law cannot be applied to them as law.


But the version of this objection with which Hart is concerned is that a state can limit itself, but only by self-imposed obligations, e.g. by signing a treaty. This is not at first sight necessarily an objection to the existence of international law, since one might hold, with Kelsen, though, as we shall see, not Hart himself, that the basic norm of international law, i.e. the principle from which its obligations are ultimately deduced, is the principle that treaties should be kept, pacta sunt servanda, a position which Kelsen developed in his account of International Law (Kelsen, 1949). But Hart points out that no argument has yet been produced to support the thesis that all a state’s obligations must be self-imposed: ‘Is there anything to support it besides the fact that it has often been repeated?’ (p.224).


Moreover, there are at least two situations in which it is agreed that a state is bound by international law even though it has signed no treaty. First, (p.226) ‘It has never been doubted that when a new, independent state emerges into existence…it is bound by the general obligations of international law’; and it does not have the option of refusing to be bound by them. Secondly, a state may change, for example by acquiring territory, in such a way that it automatically comes under new obligations: Hart’s example is of a previously land-locked state acquiring a coastline, and thereby automatically becoming subject to all the rules governing territorial waters. So we may conclude that so far there is no reason to deny that states can be and are legally bound, and not only because they have voluntarily bound themselves: the claim that this is logically impossible has no argument to support it, and requires us to suppose that the whole international body is systematically mistaken about the nature of a state’s obligations without being able to explain why this universal error exists. We should note also that according to Hart these examples of a state acquiring obligations in ways other than by signing a treaty show that the principle that treaties should be kept cannot be a basic principle supporting the whole of international law, but would be one principle out of several (pp.233-4).


But there is another objection to regarding international law as law, which is seen by Hart as much stronger but still not conclusive. It is the argument that the obligations imposed by international law are largely unenforceable; and are therefore moral rather than legal. International law can be enforced against defeated countries, or weak countries, or countries which happen to be unpopular; even then, its enforcement is often arbitrary and haphazard. Against strong countries, or victors, or countries in which the world is uninterested, even haphazard enforcement may be impossible. So the question is: should unenforceable obligations still be regarded as legal, or is it better to admit the unenforceability and regard them as simply moral?


If Hart’s theory of law is correct, this unenforceability is a direct consequence of the way in which international law currently differs from municipal law. In municipal law, according to Hart’s theory, there are, as was said above, primary rules giving instructions as to what one must do or refrain from doing, and secondary rules which determine how the primary rules are to be created, changed or applied. Under the secondary rules there will be a centralised system of policing and adjudication (though Hart has little if anything to say about policing), with such aims as applying the primary rules correctly, especially with regard to settling disputes, determining when they have been breached, and punishing those breaches in accordance with prescribed penalties. There will be a recognised legislature and a recognised procedure for making new law; and the sources of law, though there may be more than one, (e.g. statute, precedent and custom) will be clearly recognised.


In international law the situation is very different. The enforcement, such as it is, is carried out by individual states or by tribunals set up to deal with a particular set of breaches of international law, such as the Nuremberg tribunal, or the International Criminal Tribunal for the Former Yugoslavia, or the Rwanda tribunal. There has been since 2002 an International Criminal Court (this is of course since Hart’s time); but it can prosecute only if individual states are unable or unwilling to do so. There is no law-making body; and although there is agreement as to the sources of international law (see below), there is not always agreement as to whether a particular decision can be validly derived from these sources.


 In particular, it would seem that, while in municipal law there is notoriously a great problem in interpreting the documents that contain the law, in international law there can be a further problem of deciding whether or not a particular document is part of the law at all. To take an example from after Hart’s time, Lord Slynn, in giving judgement in the first case of General Pinochet (W.L.R.1456: H.L.1998), which concerned the question as to whether under international law the charges against the former ruler of Chile were such that he should be extradited from the UK to face trial, refers to ‘movements toward the recognition of crimes against international law’, seen in conventions, such as the Genocide Convention of 1948, charters setting up tribunals, decisions of national courts, the 1946 resolution of the UN General Assembly, reports of the International Law Commission and writings of jurists. He then comments that ‘some of the statements read as aspirations’, which seems to imply that at times, though not always, there is a question, about which courts may disagree, as to what is part of international law and what is still only an aim or an ideal.


 It seems, moreover, that this can go in two directions: there can be formal documents, such as UN resolutions, which nevertheless express aspirations rather than establishing law; and there can be informal statements and agreements which create legal precedents. Thus Walzer says (2006, pp.44-5):


                 <I>nternational law arises out of a radically decentralised legal system, cumbrous, unresponsive, and without a parallel judicial system to establish the specific details of the legal code…the legal handbooks are not the only place to find the war convention, and its actual existence is demonstrated …by the moral arguments that everywhere accompany the practice of war. The common law of combat is developed through a kind of practical casuistry.


 We should note that this refers to what currently is the case: it may not be inevitable. But it has the consequence not only that, as Hart points out, international law is not simply often unenforceable, but also that there is a more fundamental problem, of which unenforceability is only part. Hart takes this problem to be that international law does not have secondary rules at all, and especially does not have a basic rule of recognition: ‘the rules which are in fact operative constitute not a system but a set of rules’ (p.236). This situation might change, Hart suggests, if it became recognised that multilateral treaties could bind states which are not parties to them, and thereby have the force of law. But until that happens, on Hart’s view—and probably, he would say the same if writing today—international law is law, for reasons we will go on to discuss, but is like what he called “primitive law”, consisting of primary rules alone.


In this Hart seems to be wrong. Indeed, many writers, such as Payandeh (op. cit.) have pointed out that there are secondary rules in international law. It would be more correct to say that the secondary rules exist, but are not always clear and not always effective. The sources of international law can be stated (see below), and indeed Lord Slynn gives a list of them. They are varied; but in municipal law, rules of recognition, including the ultimate rule of recognition, may similarly have several clauses and recognise more than one source of law. There can, as we have seen, be problems of determining which documents are agreed to form part of international law, and which are disputed, because it is unclear whether they are intended to determine existing law or to establish future aims: but there is also a large area of agreement. There are a large number of courts and tribunals which can try cases under international law, and there can be disputes as to jurisdiction: but again there is a considerable area of agreement as to which courts and tribunals have this authority and how they should proceed. There are many breaches of international law which go unchallenged; but not all of them do.


Finally, though there is no central law-making body, international law does change, and there are areas of international law where it is very clear to what document appeal should be made: thus the law regulating force at sea is based on eight conventions on naval warfare adopted at the Second International Peace Conference at The Hague in 1907, updated in various sources and then consolidated in the rules issued in 1994 by the San Remo Institute of International Law. As a final point, one might suggest that, pace Hart, there is in any case no such thing as ‘primitive’ law, in his sense: all law necessarily involves rules of recognition, change and adjudication, whether or not these are made explicit. Anthropological work on law in traditional societies, such as Gluckman’s work in the 1950s on the legal process among the Barotse of Northern Rhodesia (now Zambia) seems to confirm this: see, for example, Gluckman (1965).


But although Hart may be wrong in saying that international law has no secondary rules, he might still be right in saying that a) it is still a set of rules rather than a system, and b) that it has no ultimate rule of recognition, with the result that ‘we must wait and see whether a rule gets accepted as a rule or not’, whereas if there is ‘a basic rule of recognition’ (even with several clauses), ‘we can say before a rule is actually made, that it will be valid if it conforms to the requirements of the rule of recognition.’ ( p.235). From their very different standpoints, both Lord Slynn and Walzer would seem to agree with Hart, as regards some parts of international law.


However, Hart seems to be wrong in saying there is no basic rule of recognition. For example, Article 38.1 of the Statute of the International Criminal Court lists the sources of international law as treaties; international customs and general principles, giving globally accepted standards of behaviour; judicial decisions and scholarly writings. This shows that the problem is not that a rule of recognition does not exist but that some of its clauses cannot easily be applied with precision. For example, when may scholarly writings be used to determine what the law is, and when should they be seen as simply the scholar’s personal observations? There are analogous problems in municipal law: for example, how does one decide which of a judge’s observations in giving judgement constitute the principle of the decision and set a precedent, and which are general comments? But it remains fair, I think, to say that the problem of determining what the law is in international law, though different probably only in degree from the problem in municipal law, nevertheless continues to present greater difficulties. In comparison with municipal law, international law tends to be more unclear; and not simply because a document is ambiguous, but also because it is sometimes uncertain whether the document has the force of law, even if it is agreed that it may come to do so.


Also, international law is often, though by no means always, ineffective, and lacks any central authority either to make it or to enforce it. Most crucially, perhaps, it lacks any permanent and neutral central authority to settle disputes and adjudicate whether the law has been breached and what the penalty should be. Legislation, enforcement and adjudication all take place, and can all be the work of a recognised authority, international or national, temporary or permanent; but all three are partial, haphazard to some extent, and involving several authorities rather than one. It is true that this is a long way from the state of nature imagined by political theorists, in which either justice does not exist, because there is no  authority with the power to adjudicate (a Hobbesian state of nature)  or in which individuals have to adjudicate and police for themselves (a Lockean one) . But it is also some way from the typical situation of municipal law, even though municipal law is never perfectly enforceable or perfectly clear.


This is certainly a reason for saying that international law is not ‘really’ law; but is it conclusive? Hart gives three reasons why it is not conclusive, and why we should still regard international law as law rather than morality; to these ideas, two further reasons can be added. The first point is that international law differs in structure from morality: ‘the appraisal of states’ conduct in terms of morality is recognisably different from the formulation of claims, demands, and the acknowledgements of rights and obligations under the rules of international law’ (p.228). This in itself could be construed as a difference between justice and other moral considerations; but Hart points out later on the same page that what states appeal to in disputed matters of international law are ‘references to precedents, treaties and juristic writings; often no mention is made of moral right and wrong’. That is to say that international law proceeds like other kinds of law, appealing to written documents and to precedents, and not directly to considerations of justice or human welfare. It may well be that, as in municipal law, there is a concern to interpret the documents in a way that accords with justice; but this is not the same as a direct moral appeal.


Moreover, as Hart goes on to say, there are in international law, as in law generally, rules which exist simply because there is a need for a rule, and not because in themselves they have any moral superiority to alternative rules: those who steer ships and pass each other on the right are not on that account better than those who drive cars in the UK and pass on the left. Just as municipal law has to decide such things as how many witnesses are need to make a will valid, international law has to decide such things as the width of territorial waters. Not all legal rules are of this sort, but no moral rules are: ‘a morality cannot (logically) contain rules which are generally held by those who subscribe to them to be in no way preferable to alternatives…Law, however, though it also contains much that is of moral importance, can and does contain just such rules’(p.229). Hart does not of course mean that these rules are not regarded as preferable to the absence of rules, or that any decision would be equally good, but merely that there is an arbitrary element in them, so that, though there is a moral obligation to keep to them once they have been formulated, they are not in themselves moral rules, in the way that ‘Do not steal’ is a moral rule. Morally, what is required is only that there be a rule: it is morally essential that there be a rule either that traffic keep to the right or that it keep to the left, but one rule is no better or worse than the other.


Thirdly, legal rules can be, and are, changed, added to and repealed. This is a regular feature of international law, even though there is no central law-making body, and even though repeal is rare, and the main developments are in the direction of addition and consolidation. But, though positive morality changes, it cannot be changed by fiat: racial discrimination has been made illegal in the UK, but, unfortunately, that did not mean that society from then on regarded it as morally wrong. So there are three crucial respects in which international law functions like municipal law, and in a way which is unlike morality: it appeals to documents and precedents; it contains arbitrary, though still necessary, provisions; and it can be altered by decisions of courts or treaty makers. This is probably enough to justify calling it law. But there are two further considerations, not discussed by Hart, but probably points with which he would not disagree.


Thus Hart points out, as said above, the difference between a moral appeal, e.g. to conscience, and a legal appeal to custom or precedent or a particular document. But as well as this formal difference between law and morality there can also be differences of content; not everything which is permitted by international law would be held to be morally right, and not everything which people find morally acceptable is permitted. Two contrasting examples from Walzer (2006) may be given, the cases of von Leeb and Doenitz.


The case of Field Marshal von Leeb is discussed on pp.166-7, and is an example of behaviour which is widely considered morally wrong but is permitted by international law. Von Leeb was in charge of the siege of Leningrad until December, 1941, at a time when many civilians tried to escape from the city through the German lines, which were in places very thin. These escapes, if successful, would have made it harder to starve the city into surrendering, which was the German aim. The German response was to order the prevention of escapes at all costs, including the use of artillery. It is not known how many civilians were killed by artillery or rifle fire because of these orders of September and November, 1941, or how many were deterred from trying to escape and eventually starved as a result: but it is reasonable to assume that there were some in both categories. When at Nuremberg after the war von Leeb was charged with war crimes because of these orders, his defence was that this was customary practice in wartime. The judges consulted the legal handbooks, especially Hyde’s International Law, agreed with him, and acquitted him, saying ‘We might wish the law were otherwise, but we must administer it as we find it’ (p.167).


The case of Admiral Doenitz of the German U-Boat command (pp.148-51) is in a way the reverse of this, a case of something being forbidden by international law but considered necessary by both sides.  In the “Laconia order” of 1942 Doenitz instructed submarines to strike without warning and in no way to help the crew members of a sunken ship, whether by picking them out of the water, righting their capsized lifeboats or supplying food and water, even if the ship was a merchant ship, containing non-combatants. The reason for this was that such action would increase the likelihood of detection of the submarine, which might lead to an attack on it by fighting ships in the neighbourhood and so endanger the lives of its crew. In his defence Doenitz brought evidence, including testimony from the US Admiral Nimitz, that American and British policy had been the same, and enemy survivors were not rescued if this involved additional risk. The judges held that this fact did not alter the law, as Doenitz’s counsel argued, but was a ground for not punishing him: they said that “the sentence of Doenitz is not assessed on the ground of his breaches of the international law of submarine warfare” (p.150). Doenitz in fact received the lightest sentence—10 years imprisonment—of the 19 German leaders convicted in the first set of Nuremberg trials. Again, law and accepted morality are different, but here the law is stricter, though as a result not enforced. So we may say that international law differs at times from morality, in the sense of generally accepted morality, not only in form, as Hart points out, but also in content.


A final argument for regarding international law as law is the practical benefit this brings. To regard a code of international behaviour as law gives governments a stronger motivation to adhere to it, to use it to settle disputes and to try to enforce it than would be the case if it were seen simply as a moral ideal: it shifts it, in principle and sometimes in practice, from the sphere of what it would be very desirable to do, into the sphere of what one must do. The result is that the behaviour of states towards each other, in both war and peace, is, however unsatisfactory, not as bad as it would otherwise be. There are many factors that contribute to the limitation of fraud and violence in international relations; and none of them, so far, have had a very great effect. Nevertheless, some progress has been made, and some of that progress is due to the sense that justice between nations, even when they are at war, involves strict legal obligations, for which members of governments and military commanders may be called to account, and is not merely a matter of conscience or lofty ideals. The difference between what can be achieved by appeals to conscience and what can be achieved by appeals to law may not be very large, especially if the enforcement of the law is extremely partial; but it does exist. Hence, we should agree with Hart that the crucial question is whether there are good theoretical or practical grounds for maintaining existing usage, and saying that there is international law, not merely international morality. We may then agree with him further that both for the reasons he gives himself and for the additional ones I have suggested here, there are indeed both sound theoretical and practical reasons for saying that international law, though differing in some respects from municipal law, differs in degree rather than kind, and hence is still law.


That said, one has to concede, as Hart does, that international law is often uncertain and enforced haphazardly and at the moment is always likely to be enforced in a biased rather than a fair way. One question here is whether improvement can be done by degrees and piecemeal, or requires, as some have argued, a radical rethinking of the whole structure of international law—a very important question but outside the scope of this paper. But one can at least consider the theoretical and practical consequences of this uncertainty and haphazard enforcement, which are not quite what Hart thought they were.


 First of all, given that there is sometimes, perhaps often, uncertainty as to what the law is, one needs to distinguish politically between governmental actions which are very clearly in breach of international law, and actions where this is disputable. One also needs to note that, apart from the problem of determining the law, it is in the area of international law, often particularly difficult to determine the facts. Hence statements that the actions of a particular country are or are not in accordance with international law often need to be treated with great caution. It would be a very good thing if they were made only when there was good evidence for them. The political advantages of claiming legality or illegality are probably sufficient to make this very unlikely: but at least people could learn to treat them with scepticism, and see them as political point-scoring rather than serious statements of the position of the law. Sometimes, though,  and in contrast to this, the law is clear, and clearly being violated, so that action needs, if possible, to be taken, but in fact is not. There are thus two contrasting problems: that of members of the international community asserting that there is a clear breach of international law when in fact this is uncertain, and that of a failure to speak out when the breach is very clear.


There is in parallel to this a need to remember how haphazard the enforcement of international law often continues to be. This similarly has two contrasting consequences. The first is the need to try to increase enforcement, and make bringing people to justice more normal. The second is not to do this in such a way that the gap between countries which are required to respect international law and countries which are not becomes even wider, with the weak and the unpopular on one side and the strong, the popular and those in which no one is interested on the other. So justice requires both finding ways of proceeding against those who currently are unaffected by the requirements of international law and also not being too ready to proceed when the prima facie case is poor. A very much larger and more powerful International Criminal Court, or set of courts, might be what is needed, with political independence, so that it was not at the mercy of majority political opinion in deciding when prosecutions should and should not be brought, but with wide powers to prosecute as well as to adjudicate (judges and prosecutors would of course be entirely separate). Whether this will ever come into being remains to be seen. Meanwhile, issues will presumably have to be considered case by case by those with the opportunity to prosecute, and those in a position to put pressure on them; and no doubt different countries will act differently.


For international law, though it is law, and, pace Hart, not merely ‘primitive law’, is still largely law in the making: as we have seen, there are important documents which express what is not yet law but given time will become law. The negative side of this has been pointed out above. But there is also a positive side, namely that the form international law takes can still be shaped by majority opinion in the various countries, and by the influence of majority opinion on a country’s rulers and representatives. One needs here to distinguish the general and the particular. Democratic opinion, whether in one country or several, is likely to be a bad way of deciding who should be prosecuted, what charges they should face, how specific disputes should be settled, and in general, individual cases under the law. Such opinion is always likely to be swayed by prejudice, ignorance or political advantage; and such decisions are more likely to be fair and just if in the hands of an independent judicial body.


In contrast, general legislation, and the gradual formation of the code itself, may well be made more just if as many countries as possible, and as many citizens of those countries as possible (and this may still be in practice a very small percentage) have had some hand in influencing its content. We should reject the arguments for saying that international law is not law, but point out that, as shown above, parts of it are law in the making rather than established law, so that it is appropriate for citizens anywhere in the world to have and to express opinions as to how it should develop. These points have of course been discussed by many people since Hart; but the concern of this paper has been with the particular contribution made by Hart, and with its implications, this being an area of his thought less discussed than some others but of equal importance and relevance. Our conclusions should be that Hart was right to argue that international law is law; that indeed there are further reasons, besides the ones he gives, for saying this; that he was also right to point out the problems with interpreting and enforcing international law; but that these do not make international law ‘primitive law’ (which in any case is an impossibility in practice) but rather law which in parts is still very much in the making.





an international and interdisciplinary journal of postmodern cultural sound, text and image

 Volume 11, April - September 2014, ISSN 1552-5112



Austin, JL (1961), ‘A plea for excuses’, in Philosophical Papers, Oxford: OUP



Fabre, Cecile (2011), A Cosmopolitan Theory of the Just War, Oxford: OUP



Gluckman, Max (1965), The Ideas in Barotse Jurisprudence, Manchester: MUP       



Goldsmith, JL and Posner, EA, (2005), The Limits of International Law, Oxford: OUP



Hart, HLA (1994), The Concept of Law, 2nd edition, Oxford: OUP



Hobbes, Thomas (1994) Leviathan, ed. E.Curley, Indianapolis: Hackett.



Locke, John (1993), The Second Treatise of Government, in John Locke: Political Writings, ed. D.Wootton, Harmondsworth: Penguin.



Payandeh, Mehrdad (2010), “The Concept of International Law in the Jurisprudence of HLA Hart”, European Journal of International Law, 21:4, pp. 967-995



Rodin, David (2002), War and Self-defence, Oxford: OUP



Walzer, Michael (2006), Just and Unjust Wars, 4th edition, New York: Basic Books



Winch, Peter (1958), The Idea of a Social Science, London: Routledge