treaty of Utrecht turned European balance of power into a principle of international law, or rather of the Droit public de l’Europe. The ‘universal society’ many writers referred to was still de facto a European society of Christians who had – to a certain degree – accepted religious tolerance among them as indispensable. Politicians referred to the balance-of-power doctrine to justify interventions and acquisitions such as the partitions of Poland in 1772, 1793 and 1794. Kant ridiculed this doctrine as ‘pure illusion’: it was too fragile to establish a lasting peace; it could not overcome the state of nature (VIII, 312, 29–33). On the other hand, Kant accepted that there was an entitlement to maintain a balance of power in the state of nature (VI, 346, 22–3). According to Kant, the absence of enforceable international right allows states to use military power and form alliances in order to secure their external freedom; however, this entitlement is only provisional. Kant’s position seems contradictory. It does make sense if we keep rights and entitlements, the state of nature and the juridical condition, apart.9
Eighteenth-century wars were rather limited, although sometimes wars of destruction were fought and attempts were made to make states disappear. In general, however, rulers did not want to risk their expensive professional armies, followed certain rituals and obeyed manners and politesse even in battle. Whereas going to war was usually not seen as a crime, acts in a war were subject to certain juridical norms. The international society was state-centred. As Vattel put it, the law of nations was ‘the science of the rights which exist between Nations or States, and of the obligations corresponding to these rights’.10 In theory, this implied some normative ideas: that states were moral persons and had the same basic rights, that obligations were reciprocal, and so on. Violations of these principles did occur, the partitions of Poland probably being the most prominent example. The concept of equality among states was to a large extent based on fiction.11 Finally, it must be kept in mind that for several reasons the shorthand ‘Westphalian world order’ is quite misleading. The centrality of the peace of Westphalia has to be challenged. Even before the treaty, many European states had in fact and de jure been sovereign. After Westphalia, some non-state actors did remain (partly) sovereign, or state sovereignty as a principle was ignored. All things considered, the peace treaties of Westphalia were a benchmark and key texts for inter-state relations up to Kant’s time.12
By the time of Kant, the subjects of European international relations were territorial states that had profoundly changed since the Peace of Westphalia, and that continued to do so. Princes established a political system labelled absolutism and later ‘enlightened absolutism’: they restricted the influence of the estates and the churches and built up standing armies and the bureaucracy. Their states were usually economically independent units (see chapter 1 on Prussia as a case in point).
In the course of the eighteenth century, many international lawyers turned away from natural rights theories towards positive international law. They also moved beyond the traditional focus on the ‘just war’. The question of the justice of the cause was progressively neglected, and war was seen as a political conflict. Lawyers emphasized rules that limited the conduct of war, specified diplomatic rituals, protected civilians and gave rights to neutral parties. Carl Schmitt called this Hegung of the war (diminution and mitigation; if you put war into a Gehege, then you look after it and try to reduce its dangers).13 Warfare changed profoundly only during the French Revolution, due to the formation of a citizens’ army, economic mobilization, tactical innovations and a new ideology.14 Meanwhile, the European state system remained the same, with allies finally fighting the aggressor Napoleon to prevent a ‘universal monarchy’.
Rulers, their advisers and most lawyers were not really creative in overcoming this semi-anarchical arrangement. Coalitions like the one against Louis XIV (1701–14) were formed not in order to create a system of collective security but out of necessity. These coalitions quickly fell apart, sometimes even before the end of the war: ‘War was regarded as a fact of life and as a useful instrument of diplomacy, not as a problem.’15 Systemic and long-range insights into the nature of an anarchical system came from philosophers and some jurists writing about ‘the law of nature and nations’ (they came to be called ‘international lawyers’ in the nineteenth century).
Apart from Grotius, Emer de Vattel (1714–67) was the most widely read and influential international lawyer towards the end of the eighteenth century, especially in England and the United States. Drawing upon Leibniz and Wolff, Vattel postulated a ‘universal society of the human race’ as an ‘institution of nature itself, that is, a necessary result of man’s nature’.16 He favoured popular sovereignty and replaced the sovereignty of the prince with the sovereignty of the state and its moral personality: ‘The State is not, and can not be, a patrimony.’ ‘Such a society has its own affairs and interests; it deliberates and takes resolutions in common, and it thus becomes a moral person’17 – these and other specifications have clearly influenced Kant. Vattel’s international society was pluralist in nature. Order must be kept and state independence respected. In contrast to Grotius, and in accordance with most eighteenth-century state practice, Vattel advocated a humanized law of war. Wars should be mitigated, unarmed subjects should be protected, because wars are a relation between sovereign states, not their subjects.18 Vattel’s central dilemma, however, remained unsolved: what takes precedence, the rule of law or state sovereignty? Rejecting Wolff’s idea of a great republic (civitas maxima),19 Vattel settled for absolute state independence. His law of nations was almost without any sanctions; the distinction between just and unjust wars was delegated to the sphere of morality; only the unjust enemy could be forced (see also chapter 7 on the ‘unjust enemy’). Vattel, who seldom moved away from the political realities of his age, should be seen as the typical representative of mainstream European international law, with states as the principal actors, an emphasis on state sovereignty, and clear distinctions between law and morality, international and state law, and perfect and imperfect duties.20
Although Vattel partly prepared the ground for positivism in international law, he himself was rooted in the natural right tradition. Richard Zouch, Samuel Rachel, Cornelius van Bynkershoek and Johann Jakob Moser are usually assigned to the positivist camp, even though they kept many natural right elements.21 Most international lawyers rejected Hobbes as too extreme. Hobbes had claimed that natural right justified the validity and legitimacy of positive state or civil law: Lex naturalis omnes leges civiles iubet observari.22 Laws are valid in a state or commonwealth where the sovereign can enforce them. Their inherent moral or rational features are irrelevant: Auctoritas, non veritas facit legem.23 If laws cannot be enforced, they are useless, they belong to the ius inutile. According to Hobbes, the law of nations was a case in point.
Few eighteenth-century authors were willing to follow Hobbes. Samuel Pufendorf (1632–94) agreed that international law was part of natural right. He also accepted that states live in a condition of nature, another central Hobbesian thesis.24 Parallels soon end. For Pufendorf, this condition of nature was one of peace; there was some sort of rightful order among states. Christian Wolff (1679–1754) thought that this order was rooted in the civitas maxima, a hypothetical community of states, a society of nations based on their free tacit consent, but endowed with binding laws that could not be revoked.25 Wolff distinguished among four types of international right, ius gentium naturale, voluntary international law, one based on contracts and customary law.
If Wolff was a highly original international lawyer with an idealistic touch, he was surpassed by intellectuals, philosophers and writers without professional legal training. The middle of the eighteenth century experienced a boom in peace projects. The two most prominent authors were Charles Irénée, Abbé de Saint-Pierre, and Jean-Jacques Rousseau. Saint-Pierre advocated an international organization in his Projet pour rendre la paix perpétuelle en Europe (1713).26 The task of this organization was to guarantee security for each member. This
