Abstract
This chapter traces the origin, nature and legal scope of the sovereign right to use war in international law from the fifteenth century to 1815 by researching the works of early legal scholars, for example, Balthazar Ayala, Hugo Grotius, Alberico Gentili, Francesco de Vitoria, Samuel Pufendorf, Emer de Vattel and Christian Wolff. It’s focus is the human defensive instinct which underpinned a state’s defensive exercise of this right and the scholars’ reasoning about how and why international law created the principles of immediacy, necessity and proportionality to control this right. The legal scope of the sovereign right to use war, when exercised defensively, is demonstrated to have been the imminent threat, or use, of armed force directed at the territory of a state, or that of its allies. A hypothetical definition for the legal commencement of an armed attack derived from the operation of the customary law principles of immediacy and necessity in this period is discussed.
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Notes
- 1.
Balthazar Ayala, De Jure et Officiis Bellicis et Disciplina Militari Libri III (1582); Hugo Grotius, De Jure Belli ac Pacis Libri Tres (1625); Alberico Gentili, Hispanicae Advocatiois Libri Duo (1661); Francesco de Vitoria, De Indis et de Ivre Belli Relectiones (1696); Samuel Pufendorf, De Jure Naturae et Gentium Libri Octo (1688); Emer de Vattel, The Law of Nations or the Principles of Natural Law (1758) and Christian Wolff, Jus Gentium Methodo Scientifica Perftractatum (1764).
- 2.
Grotius (1625), 91–137. His definition purposefully excluded ‘justice’ because the investigation of what can be considered a ‘just’ war was the object of his work; 34. Lassa Oppenheim, Oppenheim’s International Law (9th ed, 1992) vol 1, 1 accepted Grotius’ definition of ‘war’. He wrote in respect of the importance of recognising that it is governments that go to war for the purpose of the laws of war that ‘the laws of war belong equally to insurgents not yet recognised as a state but recognised as having belligerent rights, which they would not be if they did not possess a government.’
- 3.
Grotius (1625), 97. The limits of legal authority of private individuals during war are examined in Grotius’ Book I, 92, Book II, 172–173 and Book III, 788–791.
- 4.
Pufendorf (1688), 9 [8].
- 5.
Wolff (1764), 405 [784]–[785].
- 6.
Ibid, for example 323 [632]. His division of war into public war, private war and mixed war was the same distinction made by Grotius; 311–312 [607]–[609].
- 7.
Vattel (1758), 235 [1]. He made the distinction between ‘public war’ ‘which takes place between Nations or sovereigns, which is carried on in the name of the public authority and by its order’ and ‘private war’ which takes place between individuals’; 235 [2]–[3].
- 8.
For example John Westlake, International Law (1913) Part II, War, 1 who described war as ‘the state or condition of government contending by force’.
- 9.
Ayala (1582), vol II, 9–10, 18. See also Stephen Neff, War and the Law of Nations (2005) 31–40.
- 10.
Grotius (1625), 92, 102–137 and 164. ‘Natural law’ theory is concerned with man’s obligations as a citizen, ethics and the bounds of lawful government action and evaluates the content of laws against moral principles. For contemporary views of the early scholars work in respect of this theory see for example Ralph McInerny, ‘Thomistic Natural Law and Aristotelian Philosophy’ in John Goyette, Mark Latkovic and Richard Myers (eds) St Thomas Aquinas and the Natural Law Tradition: Contemporary Perspectives (2004) 25; Marett Leiboff and Mark Thomas, Legal Theories in Principle (2004) 54; Brian Bix, ‘Natural Law: The Modern Tradition’ in Jules Coleman and Schott Shapiro (eds), The Oxford Handbook of Jurisprudence and Philosophy of Law (2002) 61–66; David Lyons, ‘Moral Aspects of Legal Theory’ in Kenneth Himma and Brian Bix (eds) Law and Morality (2005) 109–114 and Vilho Harle, Ideas of Social Order in the Ancient World (1998) 99. Natural law theory is not identical to international customary law, the constitutive elements of which are identified in footnote 48 and are further discussed in Chapter 3, but it will be shown that the inherent right of self-defence and the principles which have historically restricted its exercise are common to both theories.
- 11.
Pufendorf (1688), 9 [8]. Man’s natural right to use war is discussed in Book VIII, 1292–1294 [880]–[881] and 1300 [885] and his restriction to do so with the establishment of the sovereign is examined at 1299 [885]. See Vitoria (1696), 167–168.
- 12.
Vattel (1758), 13–14, 235–236 [4]–[5] 235 [1].
- 13.
Wolff (1764), 9 [3], 20 [28], 28–29 [43], 129–130 [252]–[254], 139 [273], 313 [613] and 314 [615]. This is because he regarded a sovereign state, as regards to another, as a free person living in a state of nature; 9 [2].
- 14.
Ibid 6, 17–18 [22]–[25] and 19 [26]. See also Pufendorf (1688), 8, 111–112, 193 and 226–230 and Westlake (1913) Part I, Peace, 11–13, 14–19.
- 15.
Pufendorf (1688), Book II, 226 [156]; Book VII, 1118–1119 [3]–[4] and Book VIII, 1301 [885] and 1305 [889].
- 16.
Wolff (1764), 9–10 [3]–[4], 20 [28], 26 [38], 41–42 [69], 129 [252] and 313 [613]. See also Westlake (1913), 55–64.
- 17.
Especially Wolff (1764), for example, 28–30 [43]–[44] and 145 [285]. See Westlake (1913), 11–13.
- 18.
Grotius (1625), 14–15, 44, 102–103. Pufendorf (1688), 984 described a sovereign state as a ‘compound moral person, whose will, intertwined and united by the pacts of a number of men, is considered the will of all, so that it is able to make use of the strength and faculties of the individual members for the common peace and security.’ Wolff (1764), 5, 9[2] believed that a nation arose as a matter of the law of nature and regarded it as an individual free person living in a state of nature and was constituted by its individual citizens who united to form it. He described a nation succinctly at 91 [174] as ‘a number of men associated in a state.’ Sovereignty was exercised by the ruler of the state over all its land, but the principle of sovereignty was different to the principle of public or private ownership of parts of the land; 60 [102].
- 19.
For example Pufendorf (1688), Book VII, 1013 [5], 1055–1063 [722]–[727] and Book VIII, 1148 [784]; Wolff (1764), 11–13 [7]–[9] and 20–24 [28]–[34] and Vattel (1758), 235 [4]. For the views of subsequent scholars who shortly followed, see, for example, Westlake (1913), 111–121; William E Hall, International Law (8th ed, 1907) 82 and Oppenheim (1992), vol 1 [119].
- 20.
Wolff (1764), 15, 315 [617].
- 21.
In respect of the bases for the Peloponnesian condemnation of Athenian aggression and expansion see Thucydides, The Peloponnesian War (1998) 15–31. The Peloponnesians, led by Sparta and Corinth, grew after the Athenian victory over King Xerxes of Persia at the battle of Salamis (56–60). It is clear the Lacedaemonian’s decision to invade Attica in 431 B.C. was in preparation for what it claimed would be a defensive the war against Athens (60–61). However Athens also believed that it was fighting a defensive war against the Peloponnese armies when it responded to this invasion; see Pericles’ speech to Athenians at the end of the first year of the war in which he described the ‘aggression’ of the Lacedaemonians (91–97). As to the use of war by Rome to expand its empire see Adrian Keith Goldsworthy, The Roman Army at War 100 B.C.–A.D. 200 (1996) in which he describes the punitive wars launched by Rome between 53 B.C. by Julius Caesar, in 51 B.C. by Cicero and in A.D. 15 by Arminius against Germany and other European territories and peoples who might become allies of the Germans in the future (95–100). For the unique difficulties for Rome posed by using war against peoples not united by a central government see 102–103. Rome’s wars of conquest were principally used for suppression of insurrection (79–95) and for economic expansion (100–105). For the latter motivation for launching wars of conquest against Britain see Theodor Mommsen, A History of Rome under the Emperors (1996) in which he traces the campaigns of Julius Caesar, Claudius, Nero, Vespasian and Severius against the ‘semi-civilised tribes’ of Britain by Rome’s ‘occupation force’ (258–266). Mommsen explains that Rome’s military expansion of its economic power in Britain was motivated by the latter’s well developed system of commerce which provided for a sound taxation base for Rome, its rich agricultural land and mines and the fact that owners of landed estates pledged allegiance to Rome out of necessity of threat of force. For similar views of Rome’s use of war for conquest see generally Thomas Burns, Rome and the Barbarians, 100 B.C.–400 A.D. (2003); Warwick Ball, Rome in the East: the transformation of an Empire (2000); Hedley Bull, Benedict Kingsbury and Adam Roberts, Hugo Grotius and international relations (2002) 177–179. While Rome imposed a system of law throughout its empire (jus gentium) it was not a consensual system of international law developed among independent sovereign states. Jus gentium is to be distinguished from the system of law (jus civile) within Rome proper which governed its citizens; Westlake (1913), 1–3 and Ahmed Sheikh, International Law and National Behaviour: a behavioral interpretation of contemporary international law and politics (1974) 53.
- 22.
The legal characteristics of offensive and defensive just war are discussed below in Sect. 1.3.
- 23.
Grotius (1625), 103–104 and 1137–138; Wolff (1764), 130–131 [255]–[256]; Oppenheim (1992), 119–123 and Westlake (1913), 20–21.
- 24.
Wolff (1764), 91 [174]. For the numerous other duties owed by nations to each other see Chapter II, 84–139. For those duties owed by nations to themselves, see Chapter I, 20–83.
- 25.
Ibid 15 [16] where he expressed the view that the equality of sovereign states is derived from the equality of individuals as determined by natural law. See also Oppenheim (1992), 339–379.
- 26.
Wolff (1764), 130–131 [254]–[257].
- 27.
Neff (2005), 49.
- 28.
The references made by scholars to the early considerations of immediacy, necessity and proportionality in respect to the exercise of the sovereign right to use defensive war are examined in Sect. 1.4.3.
- 29.
This distinction is examined in Sect. 1.4.3. For discussions of the formal sources of law during the period of the early scholars and afterwards see for example, Westlake (1913), 14–17; Oppenheimer (1992), 23 and Article 38 of the Statute of the Permanent Court of International Justice, opened for signature 28 June 1919, (1919) UKTS 1919/4 (entered into force 10 January 1920) as enumerated later in Article 38(1) of the Statute of the International Court of Justice, opened for signature 26 June 1945, 59 Stat 1031 (entered into force 24 October 1945). International customary law is constituted by a general practice of states conducted with the relevant consideration of a legal obligation, or permission, to do so (the opinio juris).
- 30.
Vitoria (1696), 164, point 31 and 166–167.
- 31.
Ibid 167.
- 32.
Ibid 167–168. The defence of property, Vitoria believed, required a person being attacked to flee if circumstances permitted. If circumstances did not so permit, force in defence of property was permitted. However if defence was made for self in fear of physical harm no obligation rested on the person attacked to flee. He may use force without considering alternative action.
- 33.
Ibid 168.
- 34.
Ibid 169–170.
- 35.
Ayala (1582), vol II, 8–9, 11.
- 36.
Ibid 9–10, 18.
- 37.
Grotius (1625), Book I, 33, 91–137.
- 38.
Ibid 51 where Grotius examined the writings of Marcus Tullius Cicero. His study of the causes of war considered justifiable was made in Book II which is examined below.
- 39.
Ibid 52–90. Grotius uses ‘war’ to describe military force at the hands of either individuals or the sovereign state regardless of its scope. At 91 he defined ‘use of force’ as ‘when an individual tries to enforce his claim to what he thinks is due him without having recourse to a judge.’
- 40.
Pufendorf (1688), Book VIII 1294 [881] and 1298 [884].
- 41.
Wolff (1764), 314 [615].
- 42.
Vattel (1758), 235 [3]–[5].
- 43.
Brownlie (1963), 3–18 provides a more contemporary scholarly view of this theory.
- 44.
Vattel (1758), Chapter III 243–253. For other contemporary scholarly views on the theory of Just War see Hall (2006), 263–294; Lauterpacht (1952), 178; Malanczuk (1997), 306–307; McCormack (2005), 224–225; Clarke (2003), 149; Wallace (2005), 277 and Michael N Schmitt, ‘International Law and the Use of Force: The Jus ad bellum’ (2003) II The Quarterly Journal 89–97, 89.
- 45.
For example Vitoria (1696), 166. The practice of European states is only once referred to by Vitoria as ‘Custom’ at 169. He also draws on ‘human law’ which is interpreted as a reference to natural law and/or the natural behaviours of man. See Neff (2005), 49.
- 46.
Lauterpacht (1952), 177–179.
- 47.
Ibid 177 and Neville Meaney, The West and the World (1983) vol 2, 3–15.
- 48.
Ayala (1582), 10.
- 49.
Wolff (1764), 309 [603], 315 [618], 320–321 [629] and 324 [633].
- 50.
Vitoria (1696), 173, 177 and 187. However the early scholars were not united on this point. See for example Ayala (1582), 23.
- 51.
Vitoria (1696), 172–173. Only the sovereign power, including a Prince, could declare offensive war against another state; 169.
- 52.
Ayala (1582), 11–12.
- 53.
Grotius (1625), 169.
- 54.
Vitoria (1696), 170–171.
- 55.
Ibid 186 where Vitoria thought conquest was justifiable in two instances. First, ‘because of the number and aggravated quality of the damages and wrongs which have been wrought’ by an enemy state. Second, ‘when security and peace can not otherwise be had of the enemy and grave danger from them would threaten the State if this were not done.’
- 56.
Ibid 167. Vitoria did not provide a definition or criteria for distinguishing ‘good and innocent’ states from those he considered did not possess these attributes. He afforded no legal rights to rebels who stand against the sovereignty of a state. Thus, they could not possess the right to wage war nor possess a just cause for war.
- 57.
Ibid.
- 58.
Ayala (1582), 10–12; Grotius (1625), Book II, 169–171.
- 59.
Grotius (1625), 170–171, 184. Grotius considered the suffering of ‘injury’ to be the greatest cause.
- 60.
Ibid 169–185. ‘Defence’ equated to the personal and sovereign right to use defensive war.
- 61.
Pufendorf (1688), Book VIII 1294 [881].
- 62.
Wolff (1764), 321–322 [630]; 138–139 [271] and 315–316 [619]. At 315 [618] he wrote that just cause for war was ‘a wrong done or likely to be done, the war that is brought without precedent or threatened wrong is not a just war, consequently it is unjust, nor has any one a right of war except the one to whom either a wrong has been done or is offered or threatened.’
- 63.
Ibid 314 [617] where he wrote, ‘A just cause of war between nations arises only when a wrong has been done or is likely to be done’. This included the defence of all rights possessed by a state (139 [273] and 313 [613]), including a state’s right to fish the open seas; 70 [124].
- 64.
Ibid 292 [572].
- 65.
Ibid 334–335 [650].
- 66.
Vattel (1758), 244 [27] and 245 [33]–[34].
- 67.
Ibid 243 [25].
- 68.
Ibid 243 [26] and 246 [37].
- 69.
Ibid 244 [28].
- 70.
Treaty of Westphalia 1648, opened for signature 24 October 1648, 2 BFSP 1856 (entered into force 24 October 1856).
- 71.
This right continued to be considered by states in 1815 as a fundamental cornerstone of nationhood and its exercise represented a fundamental aspect of their international relations. Purposes for its exercise in 1815 and afterwards, as will be seen in Chapter 3, included the settlement of legal disputes, reprisal and intervention. See Brownlie (1963), 19 and 45 at which he describes the right of war as ‘unrestricted’. See also McCormack (2005), 224–225; Nigel Meeson, ‘Sovereignty’ (1978) 2 Encyclopedia of Public International Law 1193–1201; Peter Steinberger, ‘Sovereignty’ (1987) 10 Encyclopedia of Public International Law 397–418; Rodriguez Fowler, Julie Bunck, Law, Power and the Sovereign State: The Evolution and the Application of the Concept of Sovereignty (1995) 47–68 and Schmitt (2003), 89–90.
- 72.
Vitoria (1696), 170–171. However at 186 Vitoria believes conquest is justifiable in two instances. First, ‘because of the number and aggravated quality of the damages and wrongs which have been wrought’ by an enemy state. Second, ‘when security and peace can not otherwise be had of the enemy and grave danger from them would threaten the State if this were not done.’
- 73.
Ayala (1582), 20.
- 74.
Ibid 22.
- 75.
Ibid 10.
- 76.
Ibid 560–562, 567.
- 77.
Gentili (1661), Book I, 35–38.
- 78.
Pufendorf (1688), Book II, 226 [156].
- 79.
Ibid 227 [156] and Book VIII 1292 [2].
- 80.
Ibid Book VIII, 1293–1294 [881]. Pufendorf adopted Grotius’ causes for just war; 1296–1297 [881].
- 81.
Ibid 1295 [881].
- 82.
Wolff (1764), 90–91 [173]. He considered the law of nature to be so dominant in the theory of just war that if something was not provided for by such law then it is considered illegal and therefore, unjust; 295 [577].
- 83.
Ibid 315 [618].
- 84.
Ibid 296–297 [580].
- 85.
Ibid 316 [621].
- 86.
Ibid 316 [622] and 331 [645].
- 87.
Ibid 317 [624].
- 88.
Ibid 318 [625]. Wolff excluded the increasing power of a neighbouring state (328–329 [640]) and fortifications or the mere making plans for war (329–330 [641]) as causes for just war.
- 89.
Ibid 235 [4]. He uses ‘war’ and ‘force’ throughout his work as interchangeable terms to describe the same act, that is, military force in any form of any scale. See also the Report of Dr John Marriott, Advocate General to the Right Hon. The Earl of Halifax, 30 November 1764, Law Officers (Letter Books), H.O. 49, vol 2 in Geoffrey Cumberlege (ed), (1949) The British Year Book of International Law 1949 XXVI 6–15 in which the Advocate General rejected conquest as a national right in the Law of Nations.
- 90.
Wolff (1764), 235 [3].
- 91.
For example Vitoria (1696), 170–171, Pufendorf (1688), Book VIII 1305 [889]) and Wolff (1764), 314–315 [617]–[618] who considered that a cause for just defensive war arose when the threat of wrong-doing manifested itself (in addition to the commission of a wrong-doing). Pufendorf saw reprisal for wrong-doing as an example of defensive war in that the war defended the right to enforce redress for the wrong-doing.
- 92.
Grotius (1625), Book II, 173–175 and 549.
- 93.
Ibid Book I, 49, Book II 174–175 and 575.
- 94.
Ibid Book II, 184. See Westlake (1913), Part II, War, 19–25.
- 95.
Pufendorf (1688), Book II 264–294 [182]–[202].
- 96.
Ibid 275 [184] where he wrote, ‘For self-defence does not require one to receive the first blow or only to elude or ward off the blows which are aimed.’ However he did believe that avoidance of impending force was preferable if it could be achieved or even to endure a slight injury if doing so did not cause much detriment to the state; 267–269 [184]–[185]. The overriding motivation for exercising the right was to achieve effective defence, not revenge; 270 [186].
- 97.
Ibid 264 [182] where he wrote that the law of nature permits violence in self-defence in order to preserve safety.
- 98.
Ibid 283 [195] and Book VIII 1292 [880]. Pufendorf (1688), Book II 585 and Book III 1314 [895] agreed with Grotius on the bases for defensive war enabling sovereignty to be gained over an aggressor’s territory.
- 99.
Ibid Book VIII 1292–1294 [880]–[881] even though the municipal laws of a state that controlled the individual’s right of self-defence when a person’s life was not threatened and the international customary principles which governed the exercise of the right to use defensive war were not identical in nature. The distinction between the legal right of self-defence in both jurisdictions and the substantive rules which regulated in each jurisdiction are consistently maintained by all the early scholars.
- 100.
Ibid Book II 265 [183].
- 101.
Ibid 265 [182]. See also 272–274 [188]–[189].
- 102.
Ibid.
- 103.
Ibid 276–277 [190]–[191].
- 104.
Ibid Book II 269 [185], Book III 1298 [884] and 1302 [885]. His view is more consistent with this book’s legal definition of the commencement of an armed attack, rather than with the ‘scope and effect’ test employed by scholars after 1945, as the seriousness of the harm to a state that might be done if a particular threat of an attack took place does not determine if the right of self-defence has been lawfully exercised. If the attack is not one of a serious nature then the principle of proportionality controls the response in self-defence.
- 105.
Ibid Book II 270–271 [186], 356 [242], Book III 1294 [881] and 1296 [881].
- 106.
Ibid Book III 1305–1306 [889].
- 107.
Ibid Book II 272 [187].
- 108.
Wolff (1764), for example 315 [618]) where he wrote that ‘a wrong done or likely to be done, the war that is brought without precedent or threatened wrong is not a just war, consequently it is unjust, nor has any one a right of war except the one to whom either a wrong has been done or is offered or threatened.’ At 319 [627] he considered it a just defensive war if a sovereign state was threatened by a war that was neither justifying or persuasive and that all states have a right to use defensive war for all their security against a state that threatens such a war. See also 320 [629].
- 109.
Ibid 314 [617].
- 110.
Vattel (1758), 248 [42].
- 111.
Even when exercised justifiably but mistakenly; ibid 172–173.
- 112.
Ibid 248–249 [44]. In a material deviation from Wolff, Vattel believed that the growing strength of a neighbouring state, if it in itself became disproportionately greater than another, justified defensive war. See also Westlake (1913), 120.
- 113.
Vattel (1758), 248–249 [44].
- 114.
Ibid 246 [35]–[36]. However Vattel does not delineate between just and unjust in each conflict. He recognises the possibility both sides of a conflict can act with just cause in which the distinction between offensive and defensive war becomes unclear. In such uncertain circumstances both are considered to have acted justly until the cause is decided. See also Brownlie (1963), 6–9.
- 115.
See for example Daniel Goleman, Emotional Intelligence (1995) 7, 60, 136, 205, 227; John E Warren, Emotional Power (2004) 225–227; John Ratey, A User’s Guide to the Brain (2001) 66, 88, 114, 161–162, 171, 228–229, 232; Robert Winston, Human Instinct – How Our Primevil Impulses Shape Our Modern Lives (2002) 37–42, 49, 61–62. The logic provided by Grotius and Pufendorf at the beginning of this sub-chapter in respect of man’s instinct to defend himself from harm rather than awaiting harm and how the Law of Nations supported this action between sovereign states pertains to this work in psychology.
- 116.
Brownlie (1963), 261.
- 117.
For example Westlake (1913), 78–79.
- 118.
These considerations were not described by the early scholars as international customary law principles as they would later be described in Caroline (examined in Chapter 2). For this reason the term ‘consideration’ is used in describing their legal content at this time in history.
- 119.
Vitoria (1696), 169–179. Vitoria barely distinguished between the exercise of the right of self-defence by an individual and the justness of defensive war on the part of a sovereign state. However he distinguished between an individual’s right to use force to defend himself after the threat had passed and the sovereign right, in identical circumstances, to later avenge the wrong with defensive war; 168, 183.
- 120.
Grotius (1625), 174–175, 575.
- 121.
Ibid 184. See also Westlake (1913), 115–121.
- 122.
Pufendorf (1688), Book II 265 [182], 277 [191], Book II 274 [188]–[189], Book VIII 1293–1294 [881] and 1298–1299 [884].
- 123.
Vattel (1758), 235 [3]. He also extended these considerations to offensive war.
- 124.
For example Grotius (1625), 173 and Wolff (1764), 296–297 [580].
- 125.
Not that absolute certainty of the range of the weapon on the part of Vattel would be required before his natural right of self-defence to be legitimately exercised.
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Alder, M.C. (2013). The Use of Force Between States Before 1815 – The Sovereign Right to Use War. In: The Inherent Right of Self-Defence in International Law. Ius Gentium: Comparative Perspectives on Law and Justice, vol 19. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-4851-4_1
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