Monday, September 1, 2014

Why States go to War

 - A paper I wrote in the Fall of 2013

Reasons for War

            War. States have gone to war countless times over the history of the modern international system, and well before this system existed. A Prussian military theorist, Carl von Clausewitz who lived in through the Napoleonic Wars, once declared, “War is nothing but the continuation of policy by other means” (Clausewitz). The Correlates of War has a typology of war that looks at the state within the international system. Focusing on interstate war, meaning war between formally recognized states; one can find many factors that influence a country towards war.  Of course, there is no single set of variables that initiate wars between states and therefore one has to look at many. However, in this essay, we will look at a few variables. In particular, this paper will examine Vasquez’s key factors relating to the onset of war, including, territorial disputes, rivalry, arms races, and relative capabilities among major powers.
            To start, territorial disputes can be a major cause of war among states. In fact, a majority of wars that are fought are preceded by some sort of territorial dispute (Packer Notes 2013(a)). When one talks of territorial disputes, it is only logical that a large number of disagreements occur between neighbors with shared borders. Indeed, between 1816-1980, excluding imperial wars, every interstate war was fought between neighbors (Small and Singer, 1982). Rival territorial claims between neighbors can lead to war, with unclear defined borders being a source of dispute. Though, it is said that since 1945 territory is less of a cause for conflict, territory still revokes sentiments of national pride and prestige (Holsti 1991). Perhaps because borders are now clearly defined in a large part of the world and therefore there is less disagreement among states over territory. However there are still wars fought over territory. One such example, after 1945 was the Falklands War between Britain and Argentina fought over the Falkland Islands. The two countries fought over a piece of territory, which evoked a lot of nationalism and pride within both countries. In conclusion, territory is something that can be a source of disagreement between states in the international system. Territorial disputes can also form rivalries due to prolonged disagreement, as we will look at soon.
Rivalries exist all over the world, in many facets of life, however they also exist between states in the international system. In the interstate system, it is understood that these rivalries can have an effect on the propensity for a state to go to war. Rivals can be defined as, “a competitive relationship between two actors over an issue that is of the highest salience to them” (Vasquez 1993). These rivals have sustained mutually contingent hostile interaction with each other (Packer Notes (a)). The data shows that rivals have a greater tendency to go to war, with further study leading to the finding that of principle rivalries, three fourths of all wars were linked to rivalries (Vasquez 2012). Furthermore, a rivalry can break out over a territorial dispute between two countries. If neighbors have a disagreement about a certain piece of land, it can become a longer lasting disagreement. A long term rivalry can form between the two bordering countries over a contested territory or border. That being said, enduring rivalries also have an effect on the probability of war, Vasquez shares, “war among states involved in an enduring rivalry is comparatively high… which means they are almost four times as likely to have a war than states that have only one or two disputes (Vasquez 2012). This can be further exemplified in domestic politics of two rival countries trying to cooperate. When one side cooperates but the other does not, the country that tried to cooperate and didn’t receive reciprocation is caught with the sucker’s payoff. We know that neither country wants the sucker’s payoff, and when two countries are negotiating, the one that doesn’t arm can get the suckers payoff (Packer Lecture 2013). So, if country A & B are rivals, they are both less likely to cooperate because if one gets the suckers payoff, for instance say A does, then there is a good chance the leader of A will lose domestic support of his/her own people. Therefore, cooperation is risky for leaders of rival countries, and rivalries can add to that risk because domestic opposition will surely hold the leader accountable if they end up with the sucker’s payoff at the rival’s expense. This demonstrates how difficult it can be to cooperate and mediate disputes between rivals, and so it can lead to war. Lastly, rivalry can take the form of a power struggle between two states; an idea that Realists mostly. However, this brings us into the discussion of relative capabilities factor associated with the onset of war.
            Arms races can occur between two states that may not even have the intention of initially starting one. This occurs because when one state tries to improve its capabilities, even if in a defensive way, another state sees that as a loss in relative capability for itself. Therefore, that state now has to improve its own capabilities in response. This leads to a spiral theory, an action reaction process that ends up in an arms race. Due to the fact that A tried to enhance its security, B feels less secure. This can lead to a higher probability of war because once the spiral starts and arms race, it can be hard to stop.
Major powers have a lot more interests at stake in the international system than minor powers. When speaking of relative capabilities among these major powers, there are two schools of thought. One is the parity school, which argues that a balance of power is necessary to keep peace within the international system, and that upsetting the balance of power can cause war. Due to the relative balance of power among the major states in the system, it becomes unclear who would win a war. There is so called “structural ambiguity” that results in peace within the system (Packer Notes 2013(b)). Balance of power theory leads to the assumption that there are two ways for states to balance out the system, “external balancing” and “internal balancing”. Internal balancing occurs when the state builds up forces internally, mobilizing military power and building economic and industrial strength (Levy and Thompson 2010). This can also lead to an arms race, as stated earlier, when one country improves security, it is viewed as a loss of security for another country which then sees the need to improve its own security. Conversely, external balancing occurs when states form counterbalancing alliances against an aggressor state or with the aim to deter a potential aggressor. External balancing and alliances have an impact on war, especially when taking into account whether the alliance is made up of satisfied or dissatisfied countries. Dissatisfied powers are more likely to go to war, because they would rather go to war than continue the status quo. However, satisfied powers are benefiting from the status quo and would like to see it continue. This leads to assumptions, for instance if any one state threatens to gain hegemony then other states will form a balancing coalition against it. In that way, balance of power theorists claim that hegemons rarely form. On the other hand, the preponderance school maintains that there is anarchy without a hegemon. A Hegemon is a country with such large capabilities relative to all others that it can shoulder the cost of collective goods. This state is willing to carry the costs by providing collective security and maintaining order within the international system, allowing free riders to benefit at the expense of keeping the status quo. So, in the opposing view, when one state has a large advantage in relative capabilities, it is able to deter any would be revisionists to the system, thereby keeping the status quo in check. There is no lack of information as to who would win a war, because the hegemon has such a large advantage in relative capabilities. This leads to power transitions within the international system that can occur when a country starts to gain enough capabilities to possibly challenge the status quo. Again, it is also important to understand whether the challenger is satisfied or dissatisfied with the current system. If they are dissatisfied, then they are more likely to go to war to change the system to their favor, so-called “revisionists”. Say for instance, country A has more relative capability than country B, but country A is slowly growing or stagnating while country B is growing faster so that country B will surpass country A in capabilities at some point in the future. The defender, country A, does not know whether the challenger is satisfied or dissatisfied with the system. Therefore, country A has an incentive to launch a strike, a preventive war against country B so as to protect itself before B can catch up in relative capabilities. So a power transition between hegemons, can lead to conflict between the two states involved, the defender and the challenger. Put another way, “faced with a rising adversary, especially a potentially hostile one, a state may be tempted to fight now, when it is stronger, rather than later, when conditions are less favorable” (Levy and Thompson 2010). Again, this all depends on whether the challenger feels satisfied with the system, many argue that the power transition between the USA and the United Kingdom was peaceful because the USA was satisfied with the international system. Conversely, the transition between the UK and Germany at the start of the 20th century can be viewed as a cause of WW1 according to preponderance theorists because Germany is not viewed as having been satisfied. So, a power transition does not always have to lead to war. However, when the challenger is dissatisfied, there is a much greater chance of war because they prefer going to war over the status quo. In this way, both the parity school and the preponderance school have differing opinions on what system perpetuates peace and when there is a tendency for war within the system. In the balance of power argument, if a state tries to upset the “balance of power” system in place, it will be counterbalanced against by the status quo.
Ultimately, there are many factors that influence and affect a state’s propensity for war. Both domestic politics as well as the international system play a part as leaders face pressures and signals from both. Focusing on territorial disputes, arms races, rivalry, as well as relative capabilities among states, one is able to ascertain when states may be more likely to go to war. Taking it all into account, the study of war is complex and tough to navigate through all the factors, as each situation has a multifaceted approach for all actors involved. 


Clausewitz, Carl Von . On War. Princeton University Press, 1832. Print.

Holsti, Peace and War: Armed Conflicts and International Order, 1648-1989 (1991): 306-334

Levy, Jack, and William Thompson. Causes of War. West Sussex: Wiley-Blackwell, 2010. Print.

Packer Lecture. September 6, 2013

Packer Notes. War Typology. 2013. (a)

Packer Notes. Parity v. Preponderance. 2013 (b)

Small, M., & David, S. (1982). Resort to arms: International and civil wars, 1816-1980.

Vasquez. The War Puzzle. 1993

Vasquez. What do we know about War? New York, 2012.