1Like Grotius, Montesquieu adopts the custom that makes of war “the state of those who settle their scores by force” (De jure belli ac pacis [On the law of war and peace], I, 1, § 2). Considered as durable states to be distinguished from simple battles, wars are neither the expeditions that we see with the Ancients (Pensées, no. 300), nor the revolutions that shake despotic states (EL, V, 11), nor the invasions they make on each other (EL, IX, 5). In this sense, Montesquieu speaks following Hobbes of a state of war between individuals and between nations, while criticizing it however for having confused the state of nature – peaceful, predating societies – and the state of war, which begins as soon as men establish them (EL, I, 2-3). This parallelism between the conflicts of individuals and those of nations is provisional. Most often it is states, and not individuals, who make war: because there exist governments and tribunals, individuals in general use force only in particular cases to defend themselves: if war is a state, then the recourse to arms, if we can speak of civil war, must be a durable situation (EL, V, 11; XXX, 11).
2Since “each individual society comes to feel its strength” and a plurality of peoples is inevitable on such a large planet (EL, I, 3), war is a necessary dimension in the life of states. Montesquieu is not a pacifist. To be inept at war or to renounce it is to be condemned to servitude: the chimerical project for perpetual peace lent to Henri IV, a reference for the abbé de Saint-Pierre and Rousseau, was “bad if it had been considered in itself: the first barbarians to come along would have conquered Europe” (Pensées, no. 188).
3Wars have the same causes as other social facts: climate (northern peoples fight better than southern ones), terrain (the plain is easily invaded and the mountain difficult to conquer), the mode of subsistence (farmers are less combative than hunters and shepherds, trade inclines to peace), historical experience (people harden themselves by fighting tough adversaries and get flabby if nothing resists them), religion (intolerance tends to civil war while true Christianity tames mores), finally the political regime, in which the causes come together in various ways. A regime the principle of which is fear is ill-suited for war: wars there manifest the fury of the despot who is accustomed to encountering no resistance, rarely conducts war in person because he cannot leave the harbor of pleasure and dares not let his lieutenants conduct it because he cannot trust them (EL, V, 14). The Roman republic is “a nation ever at war and by governmental principle” (Considerations on the Romans [Romains], I). War there was “eternal”, “perpetual”, it was a genuine state. Temporary magistrates like consuls liked war “because it was the only means they had to rise above their mediocrity” (Pensées, no. 1987); constantly fatigued by the people’s complaints, the Senate sought “to distract them from their worries and occupy them elsewhere” (Romains, I); the people for its part liked war because it allowed it to enjoy the spoils of the vanquished: self-interest (the people), political calculation (the Senate) and the love of glory combined to produce “the principle of continual war” (Romains, I). In a monarchy, war is not a principle of government: it happens frequently that the prince loves war out of concern for his glory, but in periods of ambition “other passions and idleness itself follow” (ibid.). On the other hand, if despotic states “invade each other”, “monarchies alone make war” (EL, IX, 5). Taken at face value, the formula goes beyond the comparison between monarchies and despotic states and refers to the manner in which modern monarchies provide for their security, by networks of fortifications and strongholds that render war durable because victory no longer comes with a single battle and causes neither the destruction nor even the durable weakening of the defeated. Thus defined, war is invisible among the Ancients, in Asia and even in the Greece of the free republics. The Peloponnesian war was not a war of modern monarchies where the two adversaries are preserved, it lasted because the victory was long divided: “as soon as it tipped toward one side, it was suddenly obliterated” (Pensées, no. 300).
4The comparison of the three governments in their respective relation to war is thus complemented by that which intervenes between the ancients and moderns and between Europe and the rest of the world. The discoveries regarding weapons – see for example the discussion about the invention of gunpowder and bombs between Rhedi and Usbek (LP, 102 and 103]) – and military art have “equalized the strength of all men, and consequently all nations” (Monarchie universelle, I). International law has changed, which, despite the frequent gap between right and fact, has humanized war (ibid.), citizen soldiers have disappeared and armies are now composed of “the basest part of all nations” (ibid.), the resources required for maintaining troops abroad have become considerable (Monarchie universelle, I). There are also reasons proper to Europe which, within it, make any project of universal monarchy and even hegemony impossible, and which, elsewhere, favor political colonies oriented toward trade (England) rather than toward military domination (Spain). If we leave aside the historical reasons (Europe has a tradition of freedom rather than servitude), the main thing is the growing importance of trade within Europe and between Europe and the rest of the world: “it is wealth that makes for power”; since trade inclines toward peace, “Europe now is one nation made up of several” (Monarchie universelle, XVIII) or even “one state made up of several provinces (Pensées, no. 318), and “the peoples, all well-mannered, are, so to speak, members of one large republic” (Monarchie universelle, II).
5It is in this context that one can define a right to war based on true principles, in other words in line with natural insight (EL, I, 3 ; X, 2-3). Since states have the natural right to preserve themselves in their plurality, the use of defensive force (including preventive attack when a longer peace would allow the other state to destroy you) is justified: unfortunately necessary in order to defend life and the states’ freedom, war is condemned if undertaken for any other reason, glory, propriety, or utility. There is no question of endorsing the usual practices (the observed humanization does not mean that the right of real people is exactly followed, EL, X, 4), nor of endorsing the theses of modern jurists or philosophers (EL, X, 3), all of them being accused of extending the right to kill beyond what is strictly necessary for natural defense: why should the vanquishing state (the preservation of which is assured) have the right to kill and thus to enslave (Hobbes, Grotius, Pufendorf), even for punitive reasons (Grotius, Locke)? Can such a right to war which derives uniquely from necessity and from the unbending of the just found a right to conquest? The negative reply of 1721 – a society “can only be founded on the will of the associated” (LP, 92) – is corrected in L’Esprit des lois. Conquest that in itself gives no right (corrected version of the letter 92 in the post mortem edition, see the alternative (variante) 7) is allowed as a means in the service of the preservation of two states in contact with each other.
Mark H. Waddicor, Montesquieu and the Philosophy of Natural Law, The Hague: Martinus Nijhoff, 1970.
Marc Belissa, “Montesquieu, L’Esprit des lois et le droit des gens”, Le Temps de Montesquieu, Michel Porret et Catherine Volpilhac-Auger (ed.), Geneva: Droz, 2002, p. 171-185.
Jean Terrel, “À propos de la conquête : droit et politique chez Montesquieu”, Revue Montesquieu 8 (2006), http://montesquieu.ens-lyon.fr/spip.php?article330.
Jean Terrel, “Sur le livre X de L’Esprit des lois : le problème de la conquête”, Séminaire (Re)Lire L’Esprit des lois, Luigi Delia et Catherine Volpilhac-Auger dir. (ed.), in press.