War is a major subject of interest for students of international relations, and of politics more generally. The ability to wage war is viewed by some IR theorists as one of the most significant (Carr; Waltz) if not sole (Mearsheimer) sources of power and security for states today, and investigating the moral (cf. Price on weapons taboos; cf. democratic peace theory) or economic (cf. neoliberalism and Marxism) transformations that may limit war constitutes a significant research agenda for many in the field. So I’m going to write a little bit about it here.
Like the previous post, this is a short essay organising my thoughts on the subject in preparation for my comprehensive exam. Unlike the previous post, this is also intended to inform my two colleagues, also taking the exam, on a subject about which they know comparatively little. As such, it may also be of interest to non-IR students, since it will not be as laden with citations – at least at the beginning.
I’m going to answer three intertwined but, at to some extent, analytically separable questions on the subject of war:
- What is war?
- Why does war happen?
- How does war work?
I will begin somewhat more broadly and extemporaneously, but I’ll get into the nitty-gritty of IR literature a bit further in. I may try to turn this into an ‘Impatient Sceptic’s/Humanist’s Guide’ type post if there is interest, too.
1. What is War?
I’m going to proceed from the Clausewitzian dictum that war is the continuation of politics by other means. In fact, I’m going to proceed from the view that war is politics, or at least a component of a certain mode of politics: it consists in ‘an act of force designed to compel the enemy to do our will’ (Clausewitz), and thus is a political instrument. Broadening that to permit suitable social-scientific enquiry into the structures, causes, consequences, principles, and meanings that surround and constitute war as a type of social phenomenon, I will define war as follows:
War is an episode of organised, collective violence between political communities designed to resolve a conflict of interests.
This definition essentialises war in a few significant ways. First, it treats war as an attempt by actors to coerce other actors, meaning in rational terms that it seeks to make the consequences of assent less objectionable than the consequences of dissent. Second, it treats war as something that happens between political units, meaning that it must involve different groups with discrete, though not necessarily different, institutional principles or designs. While infighting within a group may involve fissioning mechanisms which eventually produce discrete units, it is not itself war. Third, it comprises acts of organised violence, where ‘violence’ is willful inflictment of physical trauma upon others and where ‘organised’ is the intentional patterning of action around principles or norms. ‘Structural violence’ (Galtung), ‘representational force’ (Mattern), or attempts to discursively undermine identity (Mitzen) are not violence by this definition , while campaigns of non-violent resistance (Gene Sharp) are not violent enough, and spontaneous eruptions of inter-communal violence (cf. McAdam, Tarrow, and Tilly) may not be well-organised enough, to count as war.
This definition also historicises and contextualises war in a few significant ways. First and foremost, it is agnostic as to what counts as interests. Interests can range from the attainment of prestige or the imposition of religion to the control of territory or the extraction of resources.  Second, it is agnostic as to what counts as a political community. Examples include kinship groups, nation-states, revolutionary insurgent groups, single-issue activists (such as environmental groups employing violent means such as terrorism), or reactionary social movements employing strategic violence. Third, it is agnostic as to what suffices as organising principles or norms. Under this definition, campaigns of targeted assaults or beatings designed to suppress or drive away opposing ethnic groups may be as much an act of war as a battle between modern military forces, though we might find many other salient differences between the two that limit our ability to treat them both as similar. Fourth, it does not require that acts of war involve violence between ‘combatants’, rendering attacks upon non-combatants – bearing in mind the socially constructed nature of these categories of persons (cite) – neither ‘merely’ terrorism nor, necessarily, an epiphenomenal or unfortunate side-effect of war.
2. Why Does War Happen?
War happens when, during a conflict of interests between political communities, one or more of those communities decides that it is appropriate to employ organised, collective violence against opposing communities as a means of coercion. Key here is the notion of propriety. One c0mmon definition of instrumental rationality is the calculation of ‘appropriate means to ends’. While this well describes the application of the utility calculus in search of efficiency, it also can describe the attempt to conform action according to norms such as moral obligations or legal procedures. It is impossible to imagine any social act which does not sit within a thick normative structure, and thus it is impossible to imagine war occurring free of moral considerations. Contrary to the maxim inter arma enim silent leges war is only possible due to a constitutive normative structure. Not only does this normative structure produce the ontological, psychological environment of discrete groups with opposing interests, it also produces the possibility of violence serving as a means of coercion. Not all willful inflicting of physical trauma will serve as a political instrument; violence must be seen as undesirable in order for the prospect of its occurrence to be a more objectionable consequence than acquiescence to the demands over which wars are fought. Most people fear death, but there are notable exceptions, under certain circumstances. Many people ‘prefer to die standing than live kneeling’, die for honour in duels , or die as hunger-strikers. So the meaning of death or injury, or rather, the social consequences of violence in terms of their effects upon identity, practice, and power, is both variable and profoundly relevant to determining when and why war is an appropriate means to ends.
The causes of war may be more or less located at three levels, or ‘images’ of society (Waltz MSW). The first is ‘human nature’: war happens because people have a ‘will to power’ that leads them to seek dominance over others (cf. Morgenthau) or are inclined towards in-group chauvinism (cf. Mercer on war and social identity theory). The corollary to this view is that people might learn a cosmopolitan morality (cf. the Enlightenment) whereby all are seen to be part of the same overarching political community, and therefore war might become obsolete. The second is that of political order: war happens because the ordering of society produces conflict. Class conflict and oligarchy (cf. Marx), ideologies of national or religious chauvinism, and pacts between warlords and merchants (cf. Tilly) leads to wars of colonial expansion, or territorial conquest. The corollary to this view is that a re-organisation of society according to, for example, communism (Marx) or liberal democracy (Kant) will produce a peaceable political community opposed to or uninterested in bellicose confrontation. The third is that of the international system itself, and it is here that the field of international relation’s most well-known thinkers have laid most of the ‘blame’ for war: from Thucydides’ account of the Peloponnesian Wars to Waltz’s ‘Theory of International Politics’ – and the slightly less influential but no less brilliant contemporaneous theory of ‘War and Change in International Politics’ (Gilpin) - war is seen to be caused by tragic circumstances of insecurity due not to inherent malevolence or ideological chauvinism but rationally justified fear and uncertainty.
Rational analyses of war tend to ‘black-box’ the social factors that make war possible and focus on the relationship between information and security. Here enters the classic ‘security dilemma’: since we cannot know whether others would be willing to coerce us, and since their doing so is a reasonable possibility (ie there are many situations wherein it could be to their benefit), it is rational to take steps to defend ourselves, but those very defensive steps also make us more of a potential danger to those others, as they are equally unsure of our willingness to coerce and because our defensive steps boost our own coercive power. Thus, even in a situation where every political community has no desire to wage war in any other situation than pure defence, it may be rational for all to prepare for war and to feel insecure. This dynamic is often modeled in game theory using the Prisoner’s Dilemma. Of course, we know that many political communities are entirely willing to initiate war, or at least to threaten to do so. Nevertheless, this still leaves the question of why wars happen. As rational choice theorists have observed, war is always costly (CITE). If parties know one-another’s capabilities, then the weaker side[s] should know that they’re going to lose the war, and thus capitulate ex ante to save themselves the costs of fighting. Ignoring for a moment the non-rational or normative factors that might nevertheless make fighting desirable even under futile circumstances, a number of important analyses offer an explanation. First, war may become less costly compared to other alternatives due to the processes of negotiation, whereby leaders who threaten war may face domestic ‘audience costs’ by reneging on that threat (Fearon 1994) or due to ‘locked’ in bargaining manoeuvres . Second, war may occur because parties have an incentive to misrepresent their capabilities, and therefore they may have private information which leads them all to conclude that they stand a good chance of winning (Fearon 1995). As a result, many rational choice theorists have searched for structures of interaction between political communities such that the security dilemma can be overcome through creating disincentives to ‘defect’ (cf. Keohane 1983) or though arms monitoring (cite?). Some variants of ‘liberal peace’ theories hold that long-term economic interaction between communities under free market conditions are enough to make harmony always preferable (Spruyt; Bueno de Mesquita), while hegemonic stability theorists (Krasner), ‘English school’ theorists of international society (Bull) and some political economists (Rodrik) see the solution to the ‘security dilemma’ as lying only in the unification of political communities under a single authority able to credibly enforce and underwrite order.
3. How Does War Work?
Usually people form up and kill one-another until all sides but one give up or everyone gets tired and they all go home. 
Hopefully this has helped to inform you, my dear colleagues and the handful of others who have bothered to read this. It has been helpful to write, at least.
 Though they may be just as coercive, just as morally objectionable, and, in another definition for another analysis, productively defined as indeed violence.
 I do not find it productive to differentiate between ‘ideational’ and ‘material’ interests, as this dichotomy collapses under any real scrutiny (cf. the philosophy of science; science)
 And as Clausewitz has observed, battles are duels writ large.
 As Schelling has observed, it can be rational to give up control under certain circumstances in order to signal resolve.
 Though as Clausewitz has observed, ‘the result in war is never final’.