THEORY OF JUST WAR IN INTERNATIONAL LAW

CHAPTER I

PHILOSOPHY OF JUST WAR IN ANCIENT GREECE AND GROUNDS OF LAWFUL WAR IN THUCYDIDES

The aim of the present chapter is, firstly, to unearth the philosophical grounds of just war in classical Greece. Secondly, to indicate specifically that neither the causes nor the theoretical grounds of the Peloponnesian War in the History of Thucydides are in conformity with previously established grounds of warfare. Thirdly, it shall be proved that the philosophical underpinnings of war in Thucydides have formed the theoretical and legal basis of contemporary kinds of military intervention in International Law. In this context, the contribution of Thucydides in the Theory of the International Law of War will be duly emphasized.

An in depth study of Greek Law and civilization in general makes manifest the existence of a concept of International Law in the ancient Greek world. It is necessary to clarify at the outset that Greek authors distinguished between unwritten (άγραφος) and written law. Unwritten law is defined by Aristotle as the universal law, that is universally recognized principles of morality, whereas written law as the statutes of any given State. Unwritten law is otherwise called natural law or divine law. This distinction is drawn in the Nicomachaean Ethics, where Aristotle suggests that: civil justice is partly natural, and partly conventional; that is natural which possesses the same validity everywhere, and does not depend on being deliberately adopted or not; while that is conventional which in the first instance does not matter whether it assumes one form or another, it matters only when it

has been laid down. A certain application of these conceptions and distinctions is seen in the sphere of the Greek Law of Nations. Writers frequently refer to “the laws of the Hellenes”, “the common laws of Hellas”, “the laws of mankind”, “the laws common to men”. Therefore, expressions such as the following are constantly used: τά τῶν Ἑλλήνων νόμιμα, τά πάντων ἀνθρώπων νόμιμα, τά κοινά τῶν Ἑλλήνων νόμιμα. A large number of important rules and practices of International Law are implied in these expressions. The underlying principles belong predominantly to the category of unwritten laws, deriving their juridical force from tradition and custom, and having for their sanction the will of the gods.

The most common grounds considered sufficient for the commencement of operations of war in classical Greece were: violation of a treaty, desertion from an alliance or confederation, offences committed against allies, refusal to receive ambassadors on invalid grounds, breach of neutrality, violation of territorial integrity, and, highly importantly, desecration of sacred places. History offers examples.

A serious injury intentionally committed against an ally was usually considered as an offence against that ally’s confederates, and so a ground for just war on part of the latter. Penelope rebuking Antinous for compassing the death of Telemachus, says: “Do you not remember how your father fled to this house in fear of the people, who were incensed against him for having joined some Taphian pirates, and plundered the Thesprotians, who were at peace with us?”

Ἡ οὐκ οἴσθ’, ὄτε δεῦρο πατήρ τεός ἴκετο φεύγων δῆμον ὑποδδείσας; δή γάρ κεχολώατο λίην, οὐνεκα ληϊστηρσιν ἐπισπόμενος Ταφίοισιν ἤκαχε Θεσπρωτούς. Οἱ δ’ἠμιν ἄρθμιοι ῆσαν.

When the province of Macedonia fell by lot to Publius Sulpicius (202 B.C.), he proposed to the people that on account of the injuries and hostilities committed against the Athenians, who were allies of Rome, they should proclaim war against Philip. In the following year the Athenians having put to death two Acarnanians for straying into their mysteries, the countrymen of the victims appealed for help to who, as they were his lawful allies, permitted them to levy troops in Macedonia. With these reinforcements they invaded Attica without a formal declaration of war. Accordingly, envoys were sent to Rome to report the attack made by an old ally of the Romans. Therefore, the Senate of Rome, in the following year, proposed to the comitia a declaration of war in consequence of this attack on a State in alliance with Rome.

Supplying assistance to the enemy belligerent, or any other flagrant act of violation of neutrality was certainly a cause of war. So, Demetri

us, during his war against the Athenians, captured a ship which was loaded with wheat bound for Athens, and hanged the captain and pilot, a measure, says Plutarch, which terrified other merchants so much that they avoided Athens, and a terrible famine pursued there.

The desecration of sacred places was especially, amongst the Hellenes, considered a cause for embarking upon just war against the offenders. Thus the reason of the Greek offensive war against the Persians was to exact just retribution for their profanation of sacred places. The Athenians declined to come to terms with Xerxes, and expressed their determination to avenge the destruction by him of their temples and images of gods and heroes.

Πρῶτα μέν καί μέγιστα, τῶν θεῶν τά ἀγάλματα καί τά οἰκήματα ἐμπεπρησμένα τέ καί συγκεχωσμένα, τοῖς ἡμέας ἀναγκαίως ἔχει τιμωρέειν ἔς τά μέγιστα μᾶλλον, ἥπερ ὁμολογέειν τῷ ταῦτα ἐργασαμένω.

The devastation of Persia by Alexander the Great provides a further proof of the vengeance exacted by the Greeks upon their enemies, primarily, if not solely, because the latter did not treat with respect the sacred locations of Hellas.

Even more emphatic was the defensive war of the Greeks when they took up arms to defend their homeland in the course of the Persian wars. Particularly their valor as shown in the navy battle of Salamis in 480 B.C., marvelously reported by Aeschylus, need be cited:

O ye sons of Hellas, go forth, free your homeland, free your women and children, the temples of your ancestral gods, the tombs of your forefathers. Now, you are fighting for them all.

(Ὤ παῖδες Ἑλλήνων, ἴτε, Ἐλευθεροῦτε πατρίδα, ἐλευθερουτε δέ παιδας, γυναίκας, θεῶν τέ πατρώων ἔδη, θήκας τέ προγόνων, νῦν ὑπέρ πάντων ἀγών)

In this context, it is of crucial significance to mention the role of Amphictionies in classical Greece. Amphictionies were alliances or confederations in ancient Greece. Amphictionies denoted the establishment of very strong political and religious ties among city-States, which shared religious ceremonies and temples. Many amphictionies existed in ancient Greece, notably that of Thermopylae, Delos, and Delphi. Delos The Delphic amphictiony was by far the most eminent and powerful. It was an international association as it was composed of twelve tribes or nations, linked with close ties of kinship. It is often referred to as the Congregation of the Greeks or, in fact, the Council of the Hellenes – τό κοινόν τῶν Ἑλλήνων Συνέδριον. There existed two categories of representatives, namely the ἱερομνήμονες, otherwise called Ἀμφικτιόνων οἱ Σύνεδροι, Councilors, and the πυλαγόραι. The former, who comprised the formal Congregation, had the privilege to demarcate the territorial boundaries of the sacred places and sacred lands. As a rule the fundamental principles that the Congregation was called to implement were decided upon and ratified through formal oath. In the case of the Delphic Amphictiony the practice of the Councilors and in essence of allies who pursued identical policies has been preserved up to nowadays and is no doubt one of the most ancient texts of treaties, providing for the formation of an alliance, in the western world. The mem

bers or Councilors, took an oath that they would in no event destroy any member city-State of the Amphictiony, nor would they cut it off from the supply of drinking water in the course of either war or peace. That they would declare war against anyone who would violate this law and should destroy their cities. That they would punish in every manner anyone that would plunder the property of the god and his accomplices in such an act.

Generally speaking, the real objective of war was to effect a reparation, previously denied, of some serious act that had without reason been inflicted, or, more importantly, to exact due revenge of a wrong in conformity and compliance with divine injunctions. Thus, Xenophon exhorted his men to have regard to moderation and honour, and not to plunder any city that was not in any way guilty of offences against them. The purpose, declares Polybius,for with which good men make war is not to destroy and annihilate the wrongdoers, but to alter the wrongful acts. Nor is it their object to involve the innocent in the destruction of the guilty – οὐ γάρ ἐπ’ἀπωλεία δεῖ καί ἀφανισμῶ τοῖς ἁγνοήσασι πολεμεῖν τούς ἀγαθούς ἄνδρας, ἀλλ’ἐπί μεταθέσει τῶν ἠμαρτημένων, οὐδέ συναιρεῖν τά μηδέν ἀδικοῦντα τοῖς ἠδικηκόσιν. This, however, has not always been the sole, let alone the most significant and justifiable, aim of war among the Greeks. The same aforementioned doctrine had long before been affirmed by Plato. In the Republic, where Socrates and Glaucon discuss what acts ought to be forbidden in warfare, but distinguish between war against Greeks and that against barbarians, Socrates suggests that the armed conflict, with the Greeks, must be conducted entirely with a view to conciliation. The

rule ought to be not enslavement or destruction of the enemy. “And as they are Hellenes themselves they will not devastate Hellas, nor they burn houses, nor even suppose that the whole population of a city –men, women, and children- are equally their enemies, for they know that the guilt of war is always confined to a few persons and that the many are their friends. And for all these reasons they will be unwilling to devastate their lands and raze their houses; their enmity to them will only last until the many innocent sufferers have compelled the guilty few to give satisfaction”. Contrast, though, the firm view of Aristotle, as expressed in the Rhetoric, that punishment and just retribution ought to be in every case the predominant object - διά θυμόν καί ὀργήν τά τιμωρητικά.

If we now turn to the causes of the Peloponnesian War, one cannot but see that these very causes have little resemblance with the grounds of war as above elaborated. As a preliminary it should be stressed that this was a civil war amongst the Greeks, not an international armed conflict as the notion is nowadays comprehended. However, the war erupted between city-States of the classical Greek world, so from this perspective it may be too be termed as an inter-State war. What is more, Thucydides invented the distinction between the remote and deeper causes of the war and the immediate causes of it. The immediate causes of the Peloponnesian War are well-known and there is no need to refer to them extensively: the events at Epidamnus, the political situation in Corcyra, the Megarian decree and the incidents at Potidaea. In the History of the Peloponnesian War Thucydides considered the immediate causes, which in fact went back almost five years before the commencement of hostilities, to be less important than the remote causes, which arose from the growth of the Athenian Empire during the fifty years before the outbreak of the war. The standpoint of

Thucydides that the war was the eventual and inevitable sequence of that empire’s growth has been widely accepted among scholars and is hereby too endorsed. Thucydides’ main statement of the causes of the war runs as follows:

Διότι δ’ἔλυσαν τάς αἰτίας προύγραψα πρώτον καί τάς διαφορᾶς του μή τινά ζητησαι ποτέ ἐξ ὅτου τοσουτος πόλεμος τοῖς Ἐλλησι κατέστη. Τήν μέν γάρ ἀληθεστάτην πρόφασιν, ἀφανεστάτην δέ λόγω, τούς Ἀθηναίους ἡγοῦμαι μεγάλους γιγνομένους, καί φόβον παρέχοντας τοῖς Λακεδαιμονίοις ἀναγκᾶσαι ἔς τό πολεμοιν. Αἵ δ’ἔς τό φανερόν λεγόμεναι αἰτίαι αἰδ’ἠσαν ἑκατέρων, ἀφ’ὧν λύσαντες τάς σπονδᾶς ἔς τοόν πόλεμον κατέστησαν.

The reasons why the broke it [the peace] and the grounds of their quarrel I have first set forth, that no one may ever have to inquire for what cause the Hellenes became involved in so a great war. The truest explanation, although it has been the least often advanced, I believe to have been the growth of Athens to greatness, which brought fear to the Lacedaemonians and forced them to war. But the reasons publicly alleged on either side which led them to break the truce and involved them in the war were as follows.

The imperial policy of Athens and ambitions of its ruling elite, which became manifest particularly in the eve of the Sicilian expedition, readily justified or at least explained a policy of counter-imperialism on part of Sparta that eventually led to war. These causes are far more similar to causes of contemporary wars that are characterized by an imperial spirit, that is, wars that are usually the consequence of imperialistic ambitions.

I cannot be agreed with Kagan, who attempts to disprove the statement of Thucydides and allege that the immediate causes of the war were far more important than the remote ones. Also, economic causes of various forms

have been suggested as the real cause of the armed conflict. The proposition of Cornford that there was a party of merchants from Peiraeus who hoped to make gains by seizing control of the routes to the west through Megara, Acarnania, and Corcyra and forced Pericles to lead Athens to war is mostly an imaginary proposition. Clearly, the interest of Athens in Corcyra was strategic and not economic. Although there were aggressively imperialistic Athenians who hoped to gain economically from the extension of their empire, the mere fact is that they did not formulate Athenian policy. That policy was made by Pericles, who had previously fought them successfully and was not influenced by them at the stage of the final crisis. The interests of the merchants may only have had some part in the decision made by the Athenian people to embark upon an expedition in Sicily.

Noteworthy is a version of the Thucydidean thesis that the war was the inevitable outcome of the division of the Greek world into two power blocs. This Thucydidean view is reinforced by the weapons of contemporary political science, notably international relation theory. The condition that troubled the Greek world and brought about the war is to be found in the expression “bipolarity”. Bipolarity is used to describe a condition in which exclusive control of international politics is concentrated in two great powers solely responsible for the preservation of peace or the making of war expeditions. Such a thesis seems to be convincing, but not distinct from the remote and real causes of the war, as the influence and policies exerted by the two great States of the Greek world was actually the product of their respective inclinations, ambitions, ideologies and immanent idiosyncracies.

The more important contribution of Thucydides, however, in my view, is to be traced in the grounds of war as described in his History. In this third part

of the article, an analysis will ensue indicating that the grounds, more properly the justifications, of war as elaborated by this great author in have provided the legal basis of some fundamental forms of armed intervention in the modern world, in the sphere of International Law science in particular.

The Thucydidean historical work sets an authoritative example of the Use of Force in the sense of armed intervention in international relations. The affairs which follow should be seen in the light of the fact that the Greek cities in ancient times were States themselves. First, Book IV of the History of the Peloponnesian War, may at first sight be said to pose an example of self-defence in International Law, particularly of protection of nationals abroad, this being a facet or category of self-defence of States. On its way to Sicily the Athenian fleet was met with a sea storm, which forced the ships to seek refuge in the Peloponnese (Pylos). Since the war between Athens and Sparta was at its height the Athenian navy members were arrested by the Lacedaemonians. Cleon, the Athenian demagogue, forcefully urged the Athenian Assembly for a military campaign to prevent their fellow citizens from being massacred. The incident may be described as an operation to save nationals abroad (since the Athenian prisoners of war were not subjects of the Spartans).

In modern International Law serious efforts have been made to limit the use of force by States. One of the cornerstones of International Law is the general prohibition of the Use of Force as enshrined in the Charter of the United Nations. UN Charter Article 2(4) provides: all members shall refrain in

their international relations from the threat or use of force against the territorial integrity or political independence of any State, or in any manner inconsistent with the purposes of the United Nations. However, Self-Defence of States is a commonly accepted exception to the general prohibition of the Use of Force as embodied in the UN Charter. Article 51 of the Charter stipulates that: “nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a member of the United Nations, until the Security Council has taken the measures necessary to maintain international peace and security. Measures taken by Members in the exercise of this right of self-defence shall be immediately reported to the Security Council and shall not in any way affect the authority and responsibility of the Security Council under the present Charter to take at any time such action as it deems necessary in order to maintain international peace and security”. The protection of nationals abroad forms one of the four facets of the right to Self-Defence. An attack against nationals of a State who happen to be abroad or failure for them to be succored in accordance with International Law stipulations, gives the right to this State to use armed force in order to protect its nationals without securing the consent of the foreign government. The right of a State to take military action to protect its nationals in mortal danger is recognized by all legal authorities in International Law. In Self Defence in International Law, Professor Bowett states, on page 87, that the right of the State to intervene by the use or threat of force for the protection of its nationals suffering injuries within the territory of another State is generally admitted, both in the writings of jurists and in the practice of States.

On June 27, 1976, an Air France airliner bound for Paris from Tel Aviv was hijacked over Greece after leaving Athens airport. Two of the hijackers appear to have been West German nationals; the other two held Arab passports. The airliner was diverted to Entebbe airport in Uganda where the Jewish passengers (about 100) were separated from the others and the latter released. The hijackers demanded the release of about 50 Palestinian terrorists imprisoned in various countries. The evidence seems to suggest that Uganda did not take such steps as it might have done against the hijackers and, indeed, helped them, although Uganda denied this. On July 3, 1976, Israel flew transport aircraft and soldiers to Entebbe and rescued the hostages by force. The hijackers were killed during the operation, as were some Ugandan and Israeli soldiers. There was also extensive damage to the Ugandan aircraft and the airport.

The military operation at Pylos has in a magnificent manner also generated the criteria for a legitimate use of force applicable in all cases of military intervention, including self-defence. These were formulated in the speech of the Athenian General Demosthenes only a while before the commencement of the military rescue operation: ‘Men who have gathered in this venture, let no one of you wish to be esteemed a man of rationality; but, instead, with plain courage, which leaves no moment for deliberation, let him attack the opponents and even be optimistic that he will eventually be victorious. When matters reach a point of overwhelming necessity, as the present case is, crude reflection is least needed in view of the instant danger’. ). Note the striking similarity between the terminology used in this text, and the one employed in the Caroline Case 1840, which traditionally and in a universally ac-

ceptable proposition sets limits to the use of armed force in contemporary International Law: ‘It will be for Her Majesty’s Government to show a necessity of self-defence, instant, overwhelming, leaving no moment for deliberation’. These were the words of Mr. Webster, U.S. Secretary of State, to British Minister Mr. Fox (April 24, 1841). It makes one wonder whether Mr Webster, was a fervent reader of Thucydides. In fact, researches I have done into his biography have revealed that, indeed, he studied Thucydides to a significant extent. This may only be coincidental. But, it remains a true fact that the terminology used in both the at the Pylos incident and the Caroline affair is identical. And, it remains an undisputable fact that the International Law principles laid down in the Caroline Case, known at the Caroline test, were put forward some 2,400 years ago in Pylos, as reported by Thucydides in the History of the Peloponnesian War. State practice in the field of the Law of War in the twentieth century that has developed in the same pattern as the rescue operation of Pylos (and Sphacteria) affirms the principles born out of the Peloponnesian War. A criterion is that the use of force must correspond to the dictates of the proportionality principle. The Caroline case principle may be seen as one that sets limits to the use of force in general and calls for adherence to proportionality. The classic formulation of Mr Webster in this context may also be quoted: ‘…did nothing unreasonable or excessive; since the act is justified by the necessity of self-defence, must be limited by that necessity, and kept clearly within it’.

Turning back to Thucydides, and examining for a moment the war incident of Pylos from a purely philological (and political) perspective, one cannot fail to see stress the rather unfair treatment of Cleon on part of Thucydides. In paragraph 28.5 of Book IV, where Cleon is described as struggling to persuade the Athenian assembly to undertake a military operation in Py-

los to rescue the Athenian hostages, Thucydides verbatim says: ἐνέπεσε μέν τί καί γέλωτος τή κουφολογία αὐτοῦ. Ἀσμένοις δ’ὅμως ἐγίγνετο τοῖς σώφροσι τῶν ἀνθρώπων, λογιζομένοις δυοιν ἀγαθοίν τοῦ ἑτέρου τεύξεσθαι. Ἤ Κλέωνος ἁπαλλαγήσεσθαι, ὅ μᾶλλον ἤλπιζον, ἤ σφαλείσι γνώμης Λακεδαιμονίους σφίσι χειρώσασθαι. The prejudice against Cleon is evident, though Thucydides to his credit seems to take a measured stance when he subsequently (much at the end of the Athenian military campaign) does not hesitate to emphasize the success of Cleon. Καί τοῦ Κλέωνος, καῖπερ μανιώδης οὖσα, ἡ ὑπόσχεσις ἀπέβη (and the promise of Cleon, mad though it was, proved to be successful, paragraph 40). The proverbial objectivity of Thucydides is further confirmed at paragraph 21.3, where it is stated that Cleon was a prominent and most influential demagogue. That statement, of course, is carries some irony, but still accurately depicts Cleon himself, who, indeed, exerted influence among the populace.

Cornford’s view that Thucydides emphasized and exaggerated the element of chance in the Athenian victory, in order, according to him, to minimize Cleon’s success, in reality it would serve rather to minimize that of Demosthenes, with whom Thucydides is generally supposed to have been on friendly terms. The war incident at Pylos and Sphacteria was certainly af-

fected by the fortune of war, not chance in the strict sense of the word. The navy battle which took place in the harbor of Pylos remains one of the most impressive ones in the history of naval warfare, and it is worth quoting the historian at this point.

The military operation at Pylos can also be viewed as a paradigm example of unilateral humanitarian intervention, if by extension of the doctrine of self-defence one accepts the existence of a similar right of intervention for humanitarian purposes. The speech of General Demosthenes again lays down the premises of humanitarian intervention. A State can lawfully use armed force to prevent humanitarian catastrophe of its nationals, especially if such a danger is imminent. Such was the action of the Athenian State in Pylos. And, certainly, in modern International Law this form of the use of force should conform to the requirements of the principle of proportionality as this was developed in the Caroline Case, cited above. A UK Foreign Office Policy Document gives an accurate definition of humanitarian intervention: ‘a substantial body of opinion and of practice has supported the view that when a State commits cruelties against and persecution of its nationals in such a was as to deny their fundamental human rights and to shock the conscience of mankind, intervention in the interests of humanity is legally permissible’.

To put this issue into a contemporary context and to address the fundamental issue of the moral justification of humanitarian intervention would require a whole inquiry into the ethical foundations of the international legal system. The tension focusses between sovereignty and human rights.

At first sight there is a legal duty to refrain from interfering in the internal affairs of other States. Each State is bound to respect the sovereignty of its neighbour States. This view has its roots in legal positivism. The German philosopher Wolff was the first to separate the international law principles from the ethics of the individual. Great academic debate has erupted over the general prohibition of the use of force as stipulated in Article 2(4) of the UN Charter, especially the wording ‘against the territorial integrity or political independence of any State’.

It is necessary to show that a right of unilateral humanitarian intervention is compatible with Article 2(4) of the UN Charter. The only exceptions to the general prohibition of the threat or use of force are the ‘inherent right of individual or collective self-defence in the face of an armed attack against a State in Article 51 of the UN Charter, and enforcement actions by the Security Council or by a regional organization or group of States authorized to use force by the Security Council under Chapter VII of the Charter. Neither of these provisions is applicable to unilateral humanitarian intervention. Two arguments may be employed: that a genuine humanitarian intervention would not be a use of force against the ‘territorial integrity or political independence’ of another State, or that it would not be ‘inconsistent with the Purposes of the United Nations’. It is noteworthy that in their commentary on the Charter, Goodrich and Hambro observed that it is possible to construe the language as allowing certain limited uses of force, such as a temporary

intervention for protective purposes. Teson, noting that the promotion of human rights is as important a purpose in the Charter as the control of international conflict, concludes that to argue that humanitarian intervention is prohibited by Article 2(4) is a distortion.

Article 2(4) must be read and interpreted in conjunction with the purposes of the United Nations one of which is the promotion of human rights. The Preamble to the Charter reads as follows: ‘We the peoples of the United Nations determined…to reaffirm faith in fundamental human rights, in the dignity and worth of the human person, in the equal rights…of nations large and small…’. Article 1(3) states: ‘To achieve international co-operation in solving international problems of an economic, social, cultural, or humanitarian character, and in promoting and encouraging respect for human rights and for fundamental freedoms for all.’ Further, Article 55(c) of the Charter declares that the United Nations shall promote ‘universal respect for, and observance of human rights and fundamental freedoms for all without distinction as to race, sex, language, or religion’. More importantly, by Article 56 ‘all members pledge themselves to take joint and separate action in co-operation with the Organization for the achievement of the purposes set forth in Article 55’.

The deduction from the above should be that the right of unilateral humanitarian intervention is clearly not incompatible with Article 2(4) of the UN Charter.

Apart from the legal debate, however, I would suggest, from the moral standpoint, that the rights of States under international law derive from individual rights. The proper role of the State is to ensure protection of the rights of the individuals. As Hersch Lauterpacht very well put it, ‘states are like individuals; it is due to the fact that states are composed of individual human beings…The dignity of the individual human being is a matter of direct concern to international law’. Lauterpacht’s rationale for humanitarian intervention is that ‘ultimately, peace is much more endangered by tyrannical

contempt for human rights than by attempts to assert, through intervention, the sanctity of human personality’. Therefore, in my opinion, State sovereignty must give way to the protection of human rights whenever these are flagrantly violated. In view of the preceding theoretical discussion in this section, I strongly submit that States have a moral right, to say the least, to unilaterally intervene in cases of overwhelming humanitarian necessity. The writings of learned jurists should, in my submission, be taken much more seriously into account, and perhaps cease to be seen merely as subsidiary sources of public international law (despite Article 38(1)(d) of the ICJ Statute).

A further instance, which could have crystallized into a clear example, of humanitarian intervention in the History of Thucydides, and eventually did not materialize as such, is provided In Book III. The Island of Lesbos (member of the Athenian Empire-Commonwealth or Confederation of city-states) revolted from Athens. The Athenians set sail against the Mytilenians (inhabitants of Lesbos), and warned them that if they were to refuse an order to surrender, they would demolish their fortifications. An embassy of Mytilenians seeked the help of Sparta thus: ‘Come to the help of Mytilene. It is our lives that we are risking; an even more general calamity will follow if you will not listen to us’. The very basic criteria for humanitarian intervention were in this case fulfilled: (i) the Mytilenians were subjects of a State (Athens), (ii) they consented to the military intervention undertaken for their own sake, and (iii) they faced imminent danger of humanitarian catastrophe.

The Spartans, indeed, dispatched a fleet which reached the coast of Lesbos but never engaged in fighting. The conservative foreign policy of Sparta dictated that the military forces of the State were to keep an eye on a possible Revolt of the Helot population in the Peloponnese. This affair serves, if not else, as an instance clearly showing that humanitarian disaster may, indeed, be the outcome of non-intervention, as it eventually was with the Mytilenians. Therefore, it may be inferred that humanitarian intervention in cases of instant necessity is a must.

The History of Thucydides has undoubtedly laid down the foundations of modern International Law of War. State practice of ancient times, indeed the custom of the States of ancient Greece, cannot be neglected. The adoption of the UN Charter is not meant to suggest that pre-charter international customary law has automatically been abrogated. Instead, customary law can, indeed, be considered as part and parcel of a unified International Law tradition; as living international custom, living law, which may still find appeal in the modern world.