
Rules of War and Political Struggle Inside and Outside the State
Many are familiar with the famous statement by Carl von Clausewitz, in his book On War, that “war is a continuation of politics by other means.” The statement is famous because it articulates something that is generally true: war can be understood as an internal political dynamic projected outwards. Clausewitz’s formula — that war is the continuation of politics by other means — has an additional elegance because it can be reversed: the telescope can be turned into a microscope, and we can see the dynamics of war from the outside in, helping us understand political struggles within the state. Reversing the formula to look at politics as ‘the continuation of war by other means’ requires a bridging concept, a frame of analysis that connects — by sitting in between — politics and war. One such concept is the legal status of war. Law is a substantive element of both domestic politics and war, in that a primary purpose of law is to regulate force. Domestic law regulates force within the state, and international law regulates force outside of it — law is thus a thread of continuity that can be used to understand the ‘continuation of politics’ from the internal to the external, and vice-versa.
One of the major themes of Schmitt’s 1950 work The Nomos of the Earth is documenting the changing status of war in international law from the medieval period to his own time, the mid-twentieth century, and the intellectual foundations underlying these changes. Schmitt observes that the status of war in international law underwent three phases: first, the medieval period, in which war was waged on the principle of justa causa, or just cause; then, the period from the sixteenth through the nineteenth century, in which war was waged on the principle of justus hostis, or just enemy; and finally, our modern period, during which war is waged on the concept of justus hostis until the enemy is considered to have violated the rules of war, at which time the enemy will be treated under the principle of justa causa.
Wars waged under the principle of justa causa are punitive: they are not only meant to end the conflict, but are also meant to punish the enemy. Belligerents waging war under this principle do not recognize that their enemies have any rights, and therefore consider themselves authorized to wage destructive war on that enemy. In medieval Europe, war was considered under the principle of justa causa, and those who sought to either endorse or condemn war would first ask, “is the cause just?” before asking “is the war legal?” Those who were tasked with arbitrating the justness of a cause in medieval Europe were theologians, and the Pope had ultimate authority in determining a justa causa, as was done in proclaiming a crusade. In practice, justa causa rarely pertained to wars between Europeans, but was rather used to justify harsh measures towards outsiders: Jews and heretics in Europe, Muslims in the Middle East, and the brutal conquest of the indigenous peoples of the Americas.
In the medieval period, European powers had many treaties amongst themselves regulating various aspects of political conflict, which meant that these powers often confronted each other under the principle of justus hostis. Schmitt notes that “the ability to recognize a justus hostis [just enemy] is the beginning of international law.” The doctrine of justus hostis places belligerents on equal footing, and in so doing places various limits and restrictions on how war can be prosecuted. Schmitt calls this process of regulating the ‘bracketing’ of war. In the sixteenth century, the doctrine of justus hostis became generalized, and the central question of war was no longer “is the cause just?” but rather, “is the war legal?” And the people to settle this question of legality were not theologians but jurists. In Part II of The Nomos of the Earth, Schmitt explains this transformation from justa causa to justus hostis while discussing the work of Francisco de Vitoria, a theologian in Renaissance Spain, who, Schmitt argues, provides a unique window into the intellectual underpinnings of medieval international law. As the following passage explains, the core of the transition from the medieval to modern international law was the abandonment of moral-theological thinking, which underlay declarations of justa causa, and the embrace of the legal-political thinking, in the category of justus hostis.
We need not elaborate on the general antithesis between medieval Christian and modern civilized beliefs. In the Middle Ages, just war could be a just war of aggression. Clearly, the formal structures of the two concepts of justice are completely different. As far as the substance of medieval justice is concerned, however, it should be remembered that Vitoria’s doctrine of just war is argued on the basis of a missionary mandate issued by a potestas spiritualis that was not only institutionally stable, but intellectually self-evident. […] All significant questions of an order based in international law ultimately coalesce in a concept of just war. Consequently, this is where the heterogeneity of intentions reached its highest degree of intensity.
Despite many internal anomalies, the medieval doctrine of just war at least was grounded in the framework of a respublica Christiana. On the one hand, it distinguished various types of feuds and wars; on the other, it recognized the legal validity of the feudal right of challenge and the baronial right of resistance. It had to distinguish among feuds, wars between Christian belligerents (those subject to the church’s authority), and other wars. Crusades and missionary wars authorized by the church were eo ipso just wars, without any distinction between aggression and defense. Princes and peoples who obstinately evaded the church’s authority, such as Jews and Saracens, by definition were hostes perpetui [perpetual enemies]. All this presupposed the authority of a potestas spiritualis in international law. Medieval Christian doctrines never could be abstracted from this church authority in international law, least of all when one of the belligerents was a Christian prince.
Formally speaking, the church’s authority was decisive in the determination of just war. Accordingly, from the standpoint of substantive law, a just war was one waged ex justa causa [from just cause], i.e., for the purpose of pursuing legal demands, regardless of whether the war was aggressive or defensive, either strategically or tactically.
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Based on relations between states, post-medieval European international law from the 16h to the 20th century sought to repress the justa causa. The formal reference point for determining just war no longer was the church’s authority in international law, but rather the equal sovereignty of states. Instead of justa causa, international law among states was based on justus hostis. Any war between states, between equal sovereigns, was legitimate. Given this juridical formalization, a rationalization and humanization — a bracketing — of war was achieved for 200 years. It is sufficient (but obviously also necessary for restoration of the true image of Vitoria) to note that the turn to the modern age in the history of international law was accomplished by a dual division of two lines of thought that were inseparable in the Middle Ages. These were the definitive separation of moral-theological from juridical-political arguments, and the equally important separation of the question of justa causa, grounded in moral arguments and natural law, from the typically juridical-formal question of justus hostis, distinguished from the criminal, i.e. from becoming the object of punitive action.
The decisive step from medieval to modern international law — from the theological system of thought predicated on the church to a juridical system of thought predicated on the state — lies in this dual division. Such a step not only concerned theoretical questions of concept formation; it exemplified, both institutionally and organizationally, the profound antithesis between two concrete orders and two distinct authorities. Sociologically, it was the structural antithesis of two leading elites — politically active groups and their advisors — and of the methods and means by which their respective political convictions and opinions were formed.
The central point of the passage should be restated with maximum clarity: the entire system of modern international law and its conventions and treaties is predicated on a transferring of the conception of war from the theological realm to the legal realm, from justa causa to justus hostis.
A number of factors prompted the shift. The circumnavigation of the globe prompted a new spatial perspective beyond the simple medieval division between respublica Christiana and heathen lands. Closely linked to circumnavigation was the embrace of scientific rationalism as a worldview independent from the theological worldview of the Middle Ages. But even without the embrace of scientific rationalism, the Christian world itself was fractured by the Protestant Reformation and the ensuing wars of religion. The major international peace treaties of the sixteenth and seventeenth centuries that begin to concretize a new, modern, properly juridical international law, were treaties to settle wars of religion, particularly the Peace of Westphalia (1648), which created the modern international system of state sovereignty. The final factor was the victory of the state form over feudalism with its endless dynastic conflicts, which sometimes spun off into vicious civil wars. The switch from the medieval to the modern, from the theological to the juridical, from just cause to just enemy created a stable international system for regulating and adjudicating conflict that would last until the early twentieth century.
At the end of the First World War, the status of war in international law underwent a further modification at the behest of new powers, the United States in particular. War remained bracketed, and belligerents still related to one another under the principle of justis hostis, but only until they were seen as violating the laws of war, at which point such enemies were considered from the perspective of justa causa. Schmitt ends his theme on the status of war in international law at this point, and his final word on it is a lament that this new modification reintroduced feudalistic wars of destruction that were not only less humane, but also more persistent and unwinnable (another post explores how this aspect of war is currently being re-examined by US military leaders). A passage in Part III, Chapter 4 of The Nomos of the Earth summarizes the problem:
Interstate European wars from 1815 to 1914 in reality were regulated; they were bracketed by the neutral Great Powers and were completely legal procedures, in comparison with the modern and gratuitous police actions against violators of peace, which can be dreadful acts of annihilation. […] The essence of European international law was the bracketing of war. The essence of such wars was a regulated contest of forces gauged by witnesses in a bracketed space. Such wars are the opposite of disorder. They represent the highest form of order within the scope of human power. They are the only protection against a circle of increasing reprisals, i.e., against nihilistic hatreds and reactions whose meaningless goal lies in mutual destruction. The removal and avoidance of wars of destruction is possible only when a form for the gauging of forces is found. This is possible only when the opponent is recognized as an enemy on equal grounds — as a justus hostis. This is the given foundation for a bracketing of war.
At one extreme, war, politics requires that conflict be regulated in order to be effective, and the essence of regulation is a recognition of the enemy as a justus hostis. Such wars have necessarily limited objectives and face limitations on the methods used — on their means — and seek not the destruction of the enemy, but the adjudication of a question. The contemporary example of one country serves to illustrate the point most succinctly: consider the difference between the First Iraq War, in which the question of the Iraqi occupation of Kuwait was successfully adjudicated between states, leading to a secure Coalition victory; and the Second Iraq War, which collapsed the state structure of Iraq, leaving the terms of victory ambiguous, and led to a series of vicious civil conflicts that continue to this day. From this point, it is possible can turn the lesson inward, and consider how the history of the legal status of war provides insight into conflict within the borders of a territorial nation-state.
A first, foundational observation using the framework of analysis outlined above is that theories of the state that claim the basis of the state to be a mutually-agreed upon contrat social must be completely abandoned. While it is true that some states, in certain periods, have had this character of the social contract, but it is not the rule. The unfortunate rule is that the state is a peace process between parties who would otherwise be at war. European states, for instance, had internal processes of unification that required overcoming internal struggles, whether they be dynastic struggles (the United Kingdom and France), religious divides (Germany), or the consolidation of often antagonistic micro-states (Germany and Italy). In the Americas, states consolidated themselves through conquest, and this can be traced through various peace treaties: between European powers over possession of colonial land, between European powers and independent states, between either of these and indigenous peoples, and of course peace treaties ending civil wars. Colonizations of other parts of the world by European powers follow the same pattern. Here the essence of the state emerges most clearly: the adjudication of disputes, the mediation of opposing factions, which can be described in the vein of Thomas Hobbes as suppression of the ‘war of all against all.’ It follows that conflict internal to the state benefits from regulation, from adjudication according to the paradigm of justis hostis, and the suppression of conflict conducted on the basis of justa causa.
In states that are called liberal, the suppression of war between private groups within the state is effected by channeling conflict into discussion, while the state maintains a monopoly of force. But the equilibrium secured by liberal discussion is only valid while potentially belligerent parties relate to one another via discussion and not force. The intrustion of private force into the political sphere is antithetical to a regime of discussion, and it is the duty of the state to supress that intrusion.
Contemporary arguments for the private use of force in political affairs readily conform to the paradigm of justa causa. Two among many iternations of justa causa in the contemporary politics in the United States, for example, can be cited briefly. The first is the popular notion that the content of certain political beliefs can be so offensive to the moral compass of society that those who hold them should be prevented from discussing their views, and be met with exclusion and even private violence — and all of this while such views may in fact be legal. A second iteration is the public proclamation by certain activist groupings of an intention to defeat a political enemy ‘by any means necessary,’ or for that matter, simply advertise a willingness to pursue a variation of means. Both of these iterations deny certain rights to the enemy, and do not view the enemy on ‘equal footing,’ and therefore conform to the moral-theological framework of justa causa. Internal political struggles inspired by the principle of justa causa are likely to produce similar problems as external wars fought under its banner.
