Economic Causes of Interstate and Intrastate Wars

By Andy B. Anderson


Trade, access to resources, and development are the general economic causes of interstate and intrastate wars. This research article explains that while resource scarcity facilitates interstate conflicts, both trade and development have ambiguous effects on the origins of these wars.  On the contrary, whereas the trade’s impact on the risk of an intrastate war is not apparent, resource abundance and underdevelopment provide incentives for such conflicts. In general, the article describes how the economic causes of both types of wars represent the material incentives and deliberations that motivate societies to use force for the achievement of their objectives. International trade, as part of economic interdependence, represents the first economic root of both interstate and intrastate conflicts.  

Impact of Trade on War Causes

Trade, a part of economic interdependence, has both conflict-promoting and conflict-inhibiting effects on both interstate and intrastate wars. The economic indicators linked to trade provide the closest measurements for economic interdependence. Economic interdependence consists of two forms, such as sensitivity interdependence and vulnerability interdependence, where the opportunity costs of disrupted relations between states represent the crucial difference between these types of economic interdependences (Mansfield and Pollins, 2001, p. 847). The explanation of the effect of trade on an interstate war reveals the causal mechanism underlying such relationship.   

Interstate Wars

Although with some exceptions, liberals claim that trade generally provides disincentives for interstate wars, realists argue that trade increases the likelihood of such conflicts. Moreover, other scholars highlight the absence of the apparent connection between the probability of interstate war and economic interdependence (Mansfield and Pollins, 2001, pp. 835-837). For instance, liberals generally assert that trade diminishes the likelihood of conflicts since interstate wars negatively affect commerce both contemporaneously and prospectively. The gravity model that takes into account the distance and the sizes of trading states solidifies the conflict-reducing benefit of trade (Hegre, Oneal & Russett, 2010, p. 771). Referring to the “Kantian Tripod”, these scholars accentuate not only the importance of economic interdependence but also the relevance of international organizations and democratic regimes in reducing the risk of interstate conflicts (Mansfield & Pollings, 2001, p. 839). Dorussen (2006, p. 89), nonetheless, cautions that the trade’s pacific effect on interstate conflicts differs across industry sectors, with the most substantial benefit for manufactured, especially, mass-produced products. In contrast, realists entirely reject the trade’s potential to diminish interstate wars. Waltz (1979, p. 138) believes that economic interdependence increases the risk of an interstate war since the linkages between potential participants lead to a war. Mearsheimer (1990, p. 45) also warns that states usually fear that their enemies might stop the flow of supplies in times of war or crisis. Furthermore, some international relations scholars use historical evidence to highlight that core national interests may conflict with the systematic impact of trade on the causes of interstate conflict (Mansfield & Pollins, 2001, p. 837). Thus, trade, as part of economic interdependence, may provide incentives and disincentives for an interstate war. At the same time, international security considerations can outweigh those of global economic structure in the states’ decisions to engage in interstate armed conflicts. International trade also influences the causes of intrastate wars.

Intrastate Wars

Similar to the impact on the causes of interstate wars, international trade has dual effects on the roots of armed conflicts within states. Insurance and deterrence represent two causal mechanisms that link international trade and intrastate wars. Trade openness not only escalates the probability of smaller-scale military conflicts but also diminishes the risk of the violent and lengthy intrastate wars (Martin, Thoenig & Mayer, 2008, p. 549). Blanton and Apodaca (2007) add that although the international marketplace may not restrain the outbreak of intrastate wars, it still provides incentives towards the quick settlement of such conflicts. However, the international trade in commodities has caused and fueled long intrastate wars (Davies, 2000). For example, in the 1990s De Beers got involved in the illegal diamond trade in Sierra Leone since the company did not track the progeny of the stones. During 1991-1999 the profits from the conflict-diamonds funded the intrastate war between the “Revolutionary United Front” and the state forces that displaced half of the state’s population and killed over 75,000 people (Tamm, 2002, p. 10). The Kimberley Process currently provides certification system for monitoring diamonds from the origin to the distribution networks (Hobbs, 2014, p. 67). Thus, international trade has an ambiguous effect on the causes of intrastate wars. From one side, trade openness should decrease the probability of violent civil wars. However, the analysis of Sierra Leone’s intrastate war proves that the illegal nature of the international trade may challenge the deterrence effect of trade. The impact of international trade on the causes of both types of wars is closely related to that of the second root of such conflicts, such as access to resources.

Influence of Access to Resources on War Causes

Access to resources is another economic motivation for violence in both inter and intranational settings. Whereas resource scarcity commonly causes the outbreak of international wars, resource abundance can trigger, increase, and sustain ferocity of intrastate conflicts. The World Bank defines renewable or nonrenewable resources as “materials that occur in nature and are essential or useful to humans, such as water, air, land, forests, fish and wildlife, topsoil, and minerals” (United States Institute of Peace, 2007, p. 4). The rivalry over the access to scarce resources is another economic factor leading to international wars.

Interstate wars

The competition over access to scarce resources has frequently led to the outbreak of interstate wars. Mercantilists claimed that the primary economic interest of the states is linked with the monopoly control not only over foreign markets but also over scarce resources (Anderton, 2003, p. 211). The neo-Malthusian theory described links among the shortage of resources, population growth, as well as war outbreak (United States Institute of Peace, 2007, p. 8). In the war-population growth nexus, the state’s technological growth inevitably rises its dependence on scarce resources (Choucri and North, 1972). Moreover, the Marxist theories of international relations claim that capitalist interests frequently guide states’ foreign policy (Hobden & Jones, 2017, p. 142). For example, the problem of access to scarce resources prompted Japan to start wars with its neighbors. The state justified its aggression in Manchuria in 1931 due to the “shortage of raw materials in Japan, the rapidly expanding Japanese population, and the division of the world into economic blocs” (Townsend, 2000, p. 2). A “prerequisite to becoming a first-rate country” (Gordon, 2000, p. 2), such as the acquisition of colonies, underlined not only Japanese pursuit of regional hegemony but also its economic reasons for interstate conflicts. Moreover, Paul Wolfowitz has acknowledged that the 2003 US invasion of Iraq was about securing access to oil (Hobden & Jones, 2017, p. 142). Consequently, the competition over scarce resources has facilitated the outbreak of both past and modern interstate wars. The access to abundant resources, however, serves as one of the leading economic reasons for armed conflicts within states.

Intrastate wars

In contrast to international settings, resource abundance may trigger, increase, and sustain the violence of intrastate wars. Some states with abundant resources have experienced the so-called “resource curse,” namely, stagnation, corruption, and violence over the revenues from resources (United States Institute of Peace, 2007, p. 8). Dorusssen (2006, p. 93) agrees that the causes of intrastate wars are linked with the economic opportunities of controlling the rents from resource extortion. Collier and Hoeffler (1998, p. 567) argue that, based on utility theory, the risk and duration of intrastate conflicts are tied to gains and costs from the rebellion. Collier (2003, p. 40) also estimates that licit or illicit exploitation of natural resources was closely related to fifty-two intrastate conflicts between 1960 and 1999. His research indicates that the modern civil wars last longer since it is easier to sustain and fund the conflict. Indeed, “greed (in the sense of economic motivation) is an important factor propelling violence in a great many civil wars” (Keen, 2012, p. 759). For instance, the abundance of capturable resources increased the risk of intrastate wars in such developing world states, such as Sierra Leone, the Democratic Republic of Congo, and Angola (Murshed, 2002, p. 389). Due to competition over the control in the oil production, the outbreak of violence among Sunni, Shiites, and Kurds in Iraq reveals the link of abundant natural resource exploitation to intrastate conflict (United States Institute of Peace, 2007, p. 9). Both Khmer Rouge and the Cambodian government also used the timber revenues to subsidize their respective military activities. Thus, the abundance of resources may trigger, increase, and sustain the violence of intrastate wars. Case studies related to the access to abundant resources discuss the “greed factor” in connection with causes of intrastate conflicts. It is evident that in such cases the access to abundant resources and international trade are both critical in the outbreak of intrastate wars. Lastly, the roots of interstate and intrastate wars are also connected to economic development.  

Impact of Economic Development on War Causes

The development represents another economic factor that contributes to both interstate and intrastate wars. While the exact impact of development on international wars is ambiguous, underdevelopment is related to the outbreak of internal conflicts. The explanation of the impact of development on an interstate war describes such causal link.  

Interstate Wars

Development has both conflict-promoting and conflict-inhibiting effects on an interstate war. The proponents of democratic peace theory believe that states with developed democratic policies and economic practices are less likely to engage in wars with other democracies but more likely to fight non-democracies. However, while mature democracies do not fight each other, the democratizing states are prone to both internal and external violence (Jentleson, 2014, pp. 370-374). The highly developed nations may also fight less over assets and territory but fight more often to force adherence to preferred policies. For instance, Iraq’s Kuwait invasion in 1990 caused an interstate conflict between the United States and Iraq. While nations usually fight for the same purpose, in this conflict these developed states had opposing interests. Iraq desired the control over territory and assets whereas the United States sought to compel Iraq to respect the territorial boundaries and withdraw its military forces (Gartzke and Rohner, 2010, p. 1-7). Therefore, economic development has contrasting effects on the outbreak of interstate wars. Developed states change their objectives in using force in interstate conflicts focusing more on policy matters versus territory acquisitions. Economic development plays a more pronounced role in providing incentives for the intrastate conflicts.

Intrastate Wars

In contrast to interstate wars, the poorly designed development increases the risk of intrastate wars. The opponents of the “greed” model of intrastate wars argue that civil wars, primarily in the developing world, are motivated by economic “grievances” that include extreme poverty, systematic economic discrimination of groups based on religious or ethnic differences, and poor social conditions (Murshed, 2002, p. 389). The concept of “relative deprivation” (Gurr, 1970, p. 128), which focuses on the differences between the human goals and the opportunities to achieve such goals, underlies the “grievances” framework. According to Stewart (2000, p. 23), relative deprivation can facilitate an intrastate war, especially if such deprivation is connected to “horizontal inequalities” in regards to socio-economic circumstances, protection of collective rights, and access to power. Moreover, some scholars link intrastate wars to the destruction or the absence of social contract (Murshed, 2002, p. 388), while others illustrate that “conflict trap” connects poverty and violence (Collier et al., 2003, p.79). For example, Nepalese civil conflict between the government and the Maoist guerrillas is related to the rebels’ fight against extreme poverty, political and social discrimination, landlessness, and widespread corruption of the country’s officials. Since the 1990s the large horizontal inequalities in Nepal have been provoked by the introduction of structural adjustment programs to achieve the state’s economic liberalization (Deraniyagala, 2005). Thus, economic underdevelopment not only increases the state’s vulnerability to conflict but also deteriorates its social contract. The “grievance” argument also illustrates the importance of identity and political motivations for the outbreak of an intrastate war. 


War has always been a central and controversial feature of international relations. This comparative analysis examines the economic factors responsible for the causes of both interstate and intrastate wars. Trade, access to resources, and development are generally regarded as the most common economic motivations for interstate and intrastate wars. While resource scarcity increases conflicts, both trade and development have ambiguous effects on the causes of interstate wars. On the other hand, whereas the impact of trade on the risk of an intrastate war is vague, resource abundance and economic underdevelopment facilitate such conflicts.

Realist, liberal, and additional arguments present a rich source of ideas about economic interdependence and war. Other theories and specific case studies describe the impact of resources and development on the causes of interstate and intrastate wars. Nonetheless, additional research is required to develop new theoretical frameworks and perform empirical investigations in the ongoing debate about economic causes of modern wars. This debate needs to provide policy suggestions about the challenges for international security, such as control over the sub and transnational actors, resource regulation, strengthening state capacity, and integration of weaker states into global trade. Moreover, it needs to capture the evolving economic dynamics of both types of wars to determine its precise influence on international politics.  


Andy B. Anderson attends Norwich University where he pursues a Master of Art in International Relations and a concentration in International Security. 


Anderton, C.H. (2003). Economic theorizing of conflict: historical contributions, future possibilities. Defense and Peace Economics, 14(3), 209-222.

Blanton, R., & Apodaca, C. (2007). Economic globalization and violent civil conflict: is openness a pathway to peace? Social Science Journal, 44(4), 599.

Choucri, N., & North, R. C. (1972). Dynamics of international conflict: some policy implications of population, resources, and technology. World Politics, 24(S1), 80-122.

Collier, P., Elliott, V. L., Hegre, H., Hoeffler, A., Reynal-Querol, M., & Sambanis, N. (2003). Breaking the conflict trap: civil war and development policy (World Bank policy research report). Washington, DC: World Bank and Oxford University Press.

Collier, P., & Hoeffler, A. (1998). On economic causes of civil war. Oxford Economic Papers, 50(4), 563-573.

Davies, V. A. (2000). Sierra Leone: ironic tragedy. Journal of African Economies, 9(3), 349-369.

Deraniyagala, S. (2005). The political economy of civil conflict in Nepal. Oxford development studies, 33(1), 47-62.

Dorussen, H. (2006, February). Heterogeneous trade interests and conflict: what you trade matters. Journal of Conflict Resolution, 50(1), 87-107.

Gartzke, E., & Rohner, D. (2010, September 24). To compare or compel: war, peace and economic development (Working Paper No. 412). Zurich: University of Zurich.

Gordon, B. (March, 2000). Japan’s march toward militarism. Wesleyan University.  Retrieved from

Gurr, T. R. (1970). Sources of rebellion in western societies: some quantitative evidence. Annals of the American Academy of Political and Social Science, 391, 128-144.

Hegre, H., Oneal J.R., & Russett, B. (2010, November). Trade does promote peace: new simultaneous estimates of the reciprocal effects of trade and conflict. Journal of Peace Research, 47(6), 763-774.

Hobbs, A. (2014). The Kimberley process. World Policy Journal, 30(4), 67.

Hobden, S., & Jones, R.W. (2017). Marxist theories of international relations. In J. Baylis, S. Smith & P. Owens, (Eds.), The globalization of world politics: an introduction to international relations. (pp. 129-143). Oxford: Oxford University Press.

Jentleson, B.W. (2014). American foreign policy: the dynamics of choice in the 21st century. (5th ed.). New York: W.W. Norton & Co. 

Keen, D. (2012, July). Greed and grievance in civil war. International Affairs, 88(4), 757-777.

Mansfield, E. D., & Pollins, B. M. (2001). The study of interdependence and conflict. Journal of Conflict Resolution, 45(6), 834-859.

Martin, P., Thoenig, M., & Mayer, T. (2008, April-May). Civil wars and international trade. Journal of the European Economic Association, 6(2/3), 541-550.

Mearsheimer, J. J. (1990). Back to the future: instability in Europe after the Cold War. International Security, 15(1), 5-56.

Murshed, S.M. (2002, July). Conflict, civil war, and underdevelopment: an introduction. Journal of Peace Research, 39(2), 387-93.

Stewart, F. (2000). The root causes of humanitarian emergencies. In E. W. Nafziger, F. Stewart, & R. Vayrynen, (Eds.), War, hunger, and displacement: the origins of humanitarian emergencies. (pp. 1-42). Oxford: Oxford University Press.

Tamm, I. J. (2002). Diamonds in peace and war: severing the conflict-diamond connection. Cambridge: World Peace Foundation.

Townsend, S. (2011). Japan’s quest for empire 1931-1945. BBC. Retrieved from

United States Institute of Peace (2007). Natural resources, conflict, and conflict resolution (a study guide series on peace and conflict). Washington, DC: United States Institute of Peace.

Waltz, K. (1979). Theory of international politics. Reading: Addision-Wesley.