Oil export,external prewar support for the government,and civil conflict onset

Abstract

The literature on civil war onset focuses on the effect of oil on domestic actors but relatively little suggests its effect on external actors who can intervene in an oil-producing state, although most revenues of oil-producing states are generated by their oil export to other states. This article advances a theory of oil export, external prewar support for the government, and civil war onset. In the international oil market, although oil is a primary energy source in most states, there are few oil exporters. This implies that costs of breaking an oil trade tie are greater for an oil-importing state vis-à-vis an oil-exporting state and, thus, oil-importing states are likely to have concerns about oil-exporting states’ political instability that can cause civil conflict onset and break their oil trade ties. I hypothesize that a state’s oil export increases the likelihood of external prewar support for its government. However, because oil-exporting states are likely to conceal the information about their oil export to prevent public grievances against the distribution of oil revenues and their governments’ incompetence in oil export, rebels are less likely to have complete information about oil export. The secrecy of oil export hinders finding a mutually acceptable bargaining range between the government and rebels, and increases the likelihood of civil conflict onset in oil-exporting states without external support for the government. I measure each state’s oil export using network analysis, and test these hypotheses using logit models. Empirical results support the hypotheses.

Keywords

civil conflict onset external prewar support for the government oil market power

Introduction

In 2010, many states in the Middle East and Northern Africa (the MENA) faced a revolutionary wave, including protests, riots, and civil wars, called the Arab Spring. Previous studies have argued that political stability of states in the MENA is likely to be weakened because oil weakens their state apparatuses (Fearon & Laitin, 2003) or helps rebels to mobilize as potential financial sources (Ross, 2004; Humphreys, 2005). However, although Yemen has experienced a civil war since 2010, some states in MENA, such as Oman, have experienced only minor protests that rarely affected their regimes. The arguments in prior studies rarely explain why the two oil-producing states have experienced contrasting trends. I argue that these contrasting trends cannot be explained if we focus only on how oil affects domestic actors.

Third parties care about the MENA states’ political stability. This is because although a limited number of states, especially states in the MENA, can produce and export oil, most states use oil as a primary energy source. This exporter-favored international oil market structure makes oil-importing states more sensitive to political instability in oil-exporting states. For example, in 1979 the Iranian Revolution hindered Iran’s oil production and export to other states. The oil crisis in Iran drove up crude oil prices in the international oil market (British Petroleum, 2014) and significantly damaged oil-importing states’ economies.¹ This implies that the break of oil trade ties caused by political instability in an oil-exporting state may generate high costs to oil-importing states. Thus, I argue that oil-importing states are likely to support an oil-exporting state’s government to resolve its political instability problem and to avoid the break of their oil import ties with the exporter. However, because oil-exporting states are likely to conceal the information about their oil export to prevent public grievances against the distribution of oil revenues and their governments’ incompetence in oil export, rebels in those states are less likely to have complete information about their oil export. The secrecy of oil industries hinders finding a mutually acceptable bargaining range between the government and rebels, and increases the likelihood of civil conflict onset in oil-exporting states without external support for the government. I specify these arguments with the concept of exit costs, which considers the opportunity costs that are incurred if economic ties with a partner are severed (Crescenzi, 2003).

In order to measure the ability of a state’s oil export to attract external support, I focus on a state’s oil market power, and employ a social network approach to trade, focusing on the concept of closeness centrality in weighted networks. The main finding of this study indicates that an oil-exporting state’s oil market power encourages external support for its government while the oil market power increases the likelihood of civil conflict onset if the state does not yet experience external support for its government.

The remainder of this article is organized as follows. In the first section, a brief review of the literature on the influences of oil on civil conflict onset reveals that prior studies have focused more on how oil influences two internal actors, the government and rebels, without paying much attention to its effect on external actors, who can affect the likelihood of civil conflict onset. In the second section, I explain the concept of prewar intervention, and develop a theoretical framework to study how a state’s oil market power attracts external support for its government and how the oil market power and the external support may affect the likelihood of civil conflict onset. The third section defines the international oil trade network, and examines the influence of a state’s oil market power on external prewar support for its government and the likelihood of civil conflict onset. In the final section, I discuss the implications of the results.

Oil and civil war onset

Most prior studies on civil war onset have suggested three mechanisms by which oil increases the likelihood of civil war onset. First, some scholars have argued that grievances generated by the unjust distribution of oil revenues motivate people to mobilize rebels or participate in a rebel group (Humphreys, 2005). Because oil is generally a state-owned asset and, thus, a government decides to distribute oil revenues (Ross, 2013), residents in an oil-producing region are likely to have grievances against the distribution of oil revenues. In addition, because oil industries are generally managed by a government or a national oil company, a government may easily conceal information about oil industries (Ross, 2013), and may be motivated to exclude minority groups from state apparatuses to distribute lower oil revenues to them (Wegenast & Basedau, 2014; Asal et al., 2016). Thus, oil-funded states are more likely to experience civil war onset.

Second, the literature on civil war onset argues that oil provides incentives to establish a sovereign state (Collier & Hoeffler, 2004). Because oil increases the value of capturing the state (Fearon & Laitin, 2003), people in an oil-producing region are likely to expect that secession can provide a better future (Ross, 2013; Sorens, 2011). More recent studies have argued that although offshore oil production rarely affects civil war onset, onshore oil production encourages greedy rebels to mobilize and increases the likelihood of civil war onset (Lujala, 2010; Ross, 2013).

Third, some prior studies have emphasized that oil provides opportunities to mobilize rebels. Oil may provide the financial capabilities to mobilize and arm rebels by selling oil or booty futures to other states (Ross, 2004; Snyder & Bhaynani, 2005). In addition, because oil-funded states have less need for intrusive bureaucracies to obtain revenues from their citizens, including tax, they are likely to have weaker state apparatuses that allow rebel leaders to more easily mobilize rebels (Fearon & Laitin, 2003).

However, empirical results in prior studies have not consistently supported the three mechanisms. For example, empirical results of some prior studies reveal that oil revenues reduce the likelihood of civil war onset because they help the state buy peace (Basedau & Richter, 2014) or facilitate corruption that may placate restive groups (Fjelde, 2009) or that oil rarely affects civil war onset (Cotet & Tsui, 2013). Other scholars have argued that the effect of oil on civil war is conditional. Ross (2013) argued that oil wealth and civil war onset have a U-shaped relationship: up to a certain point the increase in oil wealth encourages civil war onset, while after that point it hinders civil war onset. Bell & Wolford (2015) revealed that oil discoveries threaten the balance of power between the government and the rebels and increase the likelihood of civil war onset, but only in poorer states.

I argue that the ambiguous empirical results have been generated by the insufficient attention paid to the effect of oil on external actors although oil revenues are generally generated by international trade. Because, in an oil-exporting state, civil conflict that can hinder its oil export damages not only the exporter but also oil-importing states, the oil-importing states may consider intervening in the exporter to prevent civil conflict onset and to avoid the break of their oil trade ties. Particularly, prior studies on civil war have revealed that external actors play a critical role in civil war (Regan, 2000). In order to more correctly analyze the effect of oil on civil conflict onset, we should consider the effect of oil not only on domestic actors but also on external actors.

In order to draw out the causal mechanisms between oil and civil conflicts, I focus on oil export and external support for an oil-exporting state’s government to avoid civil conflict. In the following section, I review the concept of prewar intervention to analyze external support for an oil-exporting state’s government to avoid civil conflict.

Prewar intervention and civil conflict

A large literature argues that external actors can affect the likelihood of civil conflict onset by altering the balance of power between the government and rebel groups and by sending signals to them (Cetinyan, 2002; Thyne, 2009). In order to analyze the effect of external actors on civil war onset, Regan & Meachum (2014) define ‘prewar interventions’ as external interventions into a state where political instability is high enough to substantively cause civil war onset but where as yet there has been no recourse to organized armed conflict. If a third party militarily (e.g. sending troops, military aid, providing intelligence, air support, military sanctions), economically (e.g. economic aid, relieving past obligations, economic sanctions), or diplomatically (e.g. mediation, international forums, the recall of ambassadors, and explicit offers to mediate by third parties that were not accepted by both sides) intervenes in a state to support the government to resolve political instability, to support a potential rebel group to encourage civil war onset, or to mediate both sides, the intervention would be a prewar intervention. For example, in 2002, the United States declared a freeze of the financial assets of the East Turkestan Islamic Movement (ETIM), a terrorist group that promoted independence for the northwestern Chinese region of Xinjiang, because the USA was trying to support China with counterterrorism cooperation (Khan, 2009). This is a prewar intervention case, because the ETIM had an obvious intention to wage a civil war to secede Xinjiang from China and consistently waged a violent separatism campaign that could cause civil war onset. However, the intervention in a politically stable state, which has little likelihood of civil war onset, is not a prewar intervention. Regan & Meachum (2014) took as an example that although Belgium can intervene in New Zealand, the intervention would not be a prewar intervention because New Zealand has little possibility of armed conflict. In sum, external prewar support for the government is a third party’s military, economic, or diplomatic intervention in a state to support its government to relieve political instability in the state. In the following section, I specify how a state’s oil export can affect external prewar support for its government with exit costs and exit cost thresholds (Crescenzi, 2003).

Oil export and external prewar support for the government

In order to analyze the effect of a state’s oil export on the likelihood of external prewar support for the government, I focus on exit costs and exit cost thresholds (Crescenzi, 2003). ‘Exit costs’ are the opportunity costs associated with alternatives, and the ‘exit cost threshold’ is the degree of exit costs beyond which a state cannot endure. Exit costs are determined by two factors: asset specificity, the degree to which an asset can be replaced by an alternative, and market structure, the possibility that a state can establish a new trade tie with an alternative trade partner. For example, if a state imports an important resource without an alternative from the market with few exporters, its exit cost would be high and would be higher than its exit costs threshold. Crescenzi (2003) argued that if the exit costs of a target that desires to remain at the status quo are greater than its exit cost threshold, a challenger who wants something from a target can use its economic tie with the target to make a demand and the target would comply. That is, an economic tie can be the bargaining leverage of a state without sacrificing the possibility of the use of military tools when necessary (Keohane & Nye, 1989).

In the international oil market, although oil is a primary energy source in most states, a limited number of states can produce and export it. This implies that an oil-importing state is vulnerable to the break of its oil import ties because its oil exit costs are likely to be higher than its oil exit cost threshold. This suggests that a state’s oil export tie can be a bargaining leverage over its oil trade partner when necessary.

Moving to the domestic realm, if an oil-exporting state is not politically stable, oil-importing states may fear that the state’s political instability might hinder its oil export and might ultimately break their oil import ties with the exporter. For example, the 1979 Iranian Revolution broke Iran’s oil export ties and damaged many oil-importing states’ economies. This reveals that an oil-exporting state as a challenger can request support from oil-importing states (its target states) by using its oil export ties, or oil-importing states may voluntarily support the state’s government to avoid the break of their oil import ties.

Thus, I argue that a state’s oil export attracts external prewar support for its government. Although third parties may neutrally intervene in a state or may support its government or a rebel group in the state to prevent civil conflict onset, I focus only on external support for the government. Because oil trade is managed by an oil-exporting state’s government or its national oil company, weakening the government can destabilize its oil export ties and can damage oil-importing states in the international oil market. Thus, I argue that oil-importing states are less likely to support a rebel group. Also, although neutral intervention might resolve political instability in an oil-exporting state, the intervention can potentially weaken its government’s power relative to a rebel group because the intervention might guarantee a rebel group’s rights and might encourage potential rebel groups to mobilize.

I argue that a state’s oil export can attract external support for its government to prevent civil conflict onset in three ways. I illustrate the three ways with two contrasting scenarios presented in Table I. First, as a state’s oil export increases, the break of its oil export ties should generate higher costs to oil-importing states. When the expected costs generated by a civil conflict in an oil-exporting state are higher than costs that oil-importing states can endure, we would expect that the oil importers try to prevent civil conflict onset in the oil exporter. Even if a state exports oil to many states, if the state does not export a substantial amount of oil to them, its oil export ties would be less likely to attract external support for its government to prevent civil conflict onset in the exporter. In the row for H1 in Table I, for example, State A exports a total of 40 metric tons of oil to two states, while State B exports a total of 30 metric tons to five states. State A is more likely to get external prewar support for its government than State B because the expected costs generated by the break of State A’s oil export ties are higher than the expected costs generated by the break of State B’s ties. This leads to the first hypothesis:

H1: As a state’s oil export volume increases, the likelihood of external prewar support for its government should increase.

Second, as the number of an oil-exporting state’s oil trade partners increases, the break of its oil export ties should damage more states in the international oil

Table I.

Hypotheses (H1–H4)

	State A (S_A)	State B (S_B)
H1: As the amount of oil export ↑, external support for the government↑
H2: As the number of oil trade partners ↑, external support for the government↑
H3: As the ability to both directly and indirectly affect oil-importing states ↑, external support for the government↑
H4: As oil market power ↑, external support for the government↑

The black node is either State A or State B, and gray nodes are its oil trade partners. Thick arrows are State A’s or State B’s direct oil export ties, and thin arrows are State A’s or State B’s indirect oil export ties. The numbers show the amount of oil that State A or State B exports to its oil trade partner.

market, and, thus, more oil-importing states should be concerned about the oil exporter’s political instability. That is, the number of an oil-exporting state’s oil trade partners indicates how many states the state can attract support for its government from. In the row for H2 in Table I, for example, although State A exports more oil than State B, State A exports oil to two states and State B exports to five states. Thus, the break of State B’s oil export ties can damage more states than the break of State A’s ties. This implies that State B would be more likely to get external prewar support for its government than State A because more states are willing to prevent the break of State B’s oil export ties. This yields the second hypothesis:

H2: As the number of an oil-exporting state’s oil trade partners increases, the likelihood of external prewar support for its government should increase.

Third, in the international oil market, an oil-exporting state’s indirect oil export ties as well as its direct oil export ties may affect oil-importing states’ economies. For example, in 2012 Russia did not export oil to Chile. Yet, Chile imported oil from the United Kingdom, which imports oil from Russia. Although Chile does not have a direct oil trade tie with Russia, the break of the oil trade tie between the UK and Russia can affect the UK’s domestic oil market and, ultimately, its oil export to other countries, including Chile. In the row for H3 in Table I, for example, although States A and B export oil to two states, State A’s oil trade partners export oil to three states while State B’s partners do not export oil. In this scenario, although both states have two oil-trade partners, the break of State A’s oil export ties can affect more states than the break of State B’s ties because of State A’s indirect oil export ties. This implies that State A would be more likely to get external prewar support for its government than State B because more states are concerned about State A’s political instability and are willing to prevent the break of State A’s oil export ties. This expectation yields the third hypothesis:

H3: As an oil-exporting state’s ability to both directly and indirectly affect oil-importing states in the international oil market increases, the likelihood of external prewar support for its government should increase.

However, because these three hypotheses focus on one of three aspects of oil export, they may ignore variation in other components and show a misleading effect of oil export on external prewar support for the government. In order to fully capture variation in oil export, we should combine them. I define the combination as ‘the market power’ of a state in the international oil market. If a state exports more oil to more states that have more oil export ties, the break of its oil export ties would more significantly damage the international oil market. Thus, as a state’s oil market power increases, oil-importing states are more willing to avoid the break of its oil export ties caused by civil conflict in the state. This expectation yields the fourth hypothesis:

H4: As the level of a state’s market power in the international oil market increases, the likelihood of external prewar support for its government should increase.

Finally, a state’s oil market power is determined not only by the state’s oil export ties but also by the international oil market’s structure. That is, even if a state exports more oil to more states than before, if there are more oil-exporting states in the international oil market than before, its oil market power might not increase because oil-importing states might rely less on the state. For example, in 1970s, the Arab–Israeli conflict significantly affected oil prices, because the Organization of Petroleum Exporting Countries (OPEC) dominated the international oil market (Smith, 2006). However, after the early 1980s, the steady entry of new oil exporters, such as Norway and the UK, and the decentralization of the international oil market has increasingly reduced OPEC states’ market power.² This expectation yields the fifth hypothesis:

H5: As the level of the international oil market’s centralization increases, the likelihood of external prewar support for an oil-exporting state’s government should increase.

Oil export, external prewar support for the government, and civil conflict onset

Although I argue that a state’s oil export attracts external support for its government to prevent civil conflict, this does not mean that the state’s oil export reduces the likelihood of civil conflict onset. Because civil conflicts occur only if actors fail to find a mutually acceptable bargaining range to resolve competing interests (Cetinyan, 2002; Thyne, 2009), unless the effect of a state’s oil export on the likelihood of external support for its government hinders finding an acceptable bargaining range, its oil export would not affect the likelihood of civil conflict onset. If the government and rebels have complete information about the other side’s bargaining power, including the other side’s capabilities and willingness to fight and the possibility of third-party interventions, they would accurately calculate an acceptable bargaining range. However, if either the government or rebels do not have complete information about the other side’s bargaining power, the government or rebels would miscalculate the other side’s bargaining power and might fail to find an acceptable bargaining range. I argue that the secrecy of oil trade is likely to cause such incomplete information situation. Oil-exporting states, especially autocratic oil-exporting states, are likely to conceal information about oil industries from the public (Ross, 2013; Asal et al., 2016), because the release of the information about oil industries to the public may engender grievances about the unequal distribution of oil wealth or the government’s incompetence in oil industries and, thus, may facilitate rebel mobilization (Ross, 2004; Humphreys, 2005; Asal et al., 2016). However, it is relatively easy to conceal the information about oil industries, because oil industries are generally managed by national oil companies or oil-exporting states’ governments (Ross, 2013). Thus, the public in an oil-exporting state may not be able to access information about the state’s oil export. This implies that rebels in the state are also less likely to have complete information about their government’s oil export and, thus, are likely to miscalculate the likelihood of external support for the government caused by its oil export. The incomplete information situation in the oil-exporting state may prevent its government and rebels from finding a mutually acceptable bargaining range. In particular, because the increase in a state’s oil market power encourages its government to expect a higher likelihood of external support from oil-importing states, the higher level of its oil market power is likely to encourage the government to suggest a more favorable point in the prewar bargaining with rebels. However, rebels might underestimate the likelihood of external support for the government, because they are less likely to have complete information about the state’s oil export. This implies that the higher level of a state’s oil market power increases the likelihood that the government’s suggestion is more favorable to the government than what rebels expect in the crisis bargaining, and, thus, is more likely to cause the bargaining failure between the government and rebels. Thus, as a state’s oil market power increases, the likelihood of civil conflict onset increases.

However, if an oil-exporting state already experiences external support for its government, rebels would be certain that its oil export may attract external support for the government from oil-importing states to avoid the break of its oil export ties. That is, even if rebels have incomplete information about their state’s oil export, external support for a state’s government as a signal from external actors to rebels may allow rebels to recognize the possibility of external support for the government attracted by its oil export. This implies that external support for an oil-exporting state’s government is likely to prevent the bargaining failure between the government and rebels generated by rebels’ incomplete information about the government’s oil export and, thus, is likely to reduce the likelihood of civil conflict onset. In sum, if an oil-exporting state does not experience external support for its government yet, its oil market power is likely to increase the likelihood of civil war onset. However, if an oil-exporting state already experiences external support for its government, its market power is less likely to affect the likelihood of civil conflict onset. This expectation yields the sixth hypothesis:

H6: An increase in the level of a state’s market power in the international oil market should increase the likelihood of civil conflict onset in the state without external support for its government, but should not affect the likelihood of civil conflict onset in the state with external support for its government.

Research design

The general expectations of this study are that as a state’s oil market power increases, external prewar support for the government to prevent civil conflict onset is more likely to occur but civil conflict onset is more likely to occur when the state does not yet experience external prewar support for its government. The unit of analysis is the country-year for all states from 1986 to 2007. I examine external prewar support for the government using Regan & Meachum’s (2014) dataset and civil conflict onset using the UCDP/PRIO Armed Conflict dataset (Melander, Pettersson & Themnér, 2016). First, external prewar support for the government is a type of prewar intervention – third-party actions prior to civil conflict to militarily, economically, or diplomatically affect political outcomes of a state that suffers from political instability but does not yet face a civil conflict (Regan & Meachum, 2014). In order to distinguish prewar interventions from other kinds of intervention, Regan & Meachum (2014) use a risk score from Goldstone et al. (2010), which indicates the likelihood that a state will experience a civil war onset within two years and is calculated by a state’s regime type, infant mortality, the presence of a conflict-prone neighborhood, and state-led discrimination. If an external actor militarily, economically, or diplomatically intervenes in a state where the risk score is higher than 0.3 but does not yet experience civil conflict, this intervention would be a prewar intervention. In order to test the hypotheses, I classify prewar interventions into three types: support for the government, neutral intervention, and support for rebels. I refer to the measure of all prewar interventions as Intervention (3.34% of all country-years), the measure of prewar interventions to support a state’s government to resolve its political instability as Government (1.00% of all country-years), the measure of neutral interventions as Neutral (1.75% of all country-years), and the measure of interventions to support a state’s rebels to facilitate civil conflict onset as Rebel (1.52% of all country-years). All prewar intervention measures are coded as dichotomous variables that take the value 1 in the year that a state experiences at least a prewar intervention and 0 otherwise. Government is a dependent variable of empirical models for Hypotheses 1–5, and all prewar intervention variables are independent variables of empirical models for Hypothesis 6. The dataset covers 163 states with populations exceeding 500,000, which results in 3,461 country-year observations.

The second dependent variable, Onset, is coded 1 for each country-year in which a civil conflict began and 0 otherwise. The UCDP/PRIO Armed Conflict dataset defines armed conflict as a ‘contested incompatibility that concerns government and/or territory where the use of armed force between two parties, of which at least one is the government of a state, results in at least 25 battle-related deaths’ (Gleditsch et al., 2002: 18). This dataset covers 163 states with populations exceeding 500,000, which includes 3,461 country-year observations.

Because the dependent variables are binary, I use logistic regression to examine the hypotheses. Standard errors are clustered by state to account for potential unobserved state-level heterogeneity. To control for temporal dependence, I include variables counting the number of years without a civil war with the cubic polynomial approximation (Carter & Signorino, 2010). All independent variables are lagged one year to avoid endogeneity problems.

Oil trade network and network centrality³

I hypothesize that a state’s oil export may affect oil-importing states in three ways: the amount of a state’s oil export, the number of an oil-exporting state’s oil trade partners, and the ability of an oil-exporting state to directly and indirectly affect oil-importing states in the international oil market. In order to capture the effect of a state’s oil export on external prewar support for the government and civil conflict onset, I employ network analysis. In network analysis, a network consists of a set of nodes (e.g. people, institutions, states) connected by a set of edges (e.g. friendship, alliance, trade) (Maoz, 2009). Because a state’s oil trade ties in the international oil market are affected by other states’ oil trade ties, oil trade ties are one kind of interactions among states. Thus, the international oil market is a network comprised of states (nodes) and their oil trade ties (edges). The network is formally represented as an n × n adjacency matrix where matrix entries x_ij indicate a tie between node i and node j. Because oil export is more influential than oil import due to the structure of the international oil market and the importance of oil as a primary energy source, oil trade ties are directed, or x_ij ≠ x_ji . I define an oil trade tie from i to j as a tie weighted by metric tons of oil that State i exports to State j. The oil trade ties are estimated by using Woo’s (2015) dataset.⁴ For a given year, the international oil trade network is represented as adjacency matrix X, which captures the totality of the oil trade network and indicates who trades oil with whom and at what levels. Based on these data, the oil trade network consists of 163 independent states and their oil trade ties with other states.

This study focuses on actor centrality, a network property associated with power and prestige of each node in a network (Borgatti, Everett & Johnson, 2013). Generally, substantive interpretation of centrality depends on the substance of the network. Because this study suggests that a state’s oil export tie may be a source of the state’s ability to attract external prewar support for the government, centrality indices in this study capture three effects of a state’s oil export on external support for its government prior to civil conflict onset. I employ three centrality indices to test the first three hypotheses: Oil export (log), Oil trade partners, and Oil export ability. First, the total amount of a state’s oil export captures costs of breaking its oil export ties. The amount of a state’s oil export is estimated by the sum value of a state’s oil export ties,

V_{i} = \sum_{j = 1}^{n} x_{i j} (i \neq j)

where x_ij denotes entries of the weighted oil trade network, X. Because the value of an oil export tie is defined as its oil export amount (metric tons), V_i is State i’s total oil export amount. I refer to its natural log as Oil export (log). This measurement is to test the first hypothesis (H1).

Second, an oil-exporting state’s number of oil trade partners captures the mechanism by which its oil export ties act as strategic tools to intentionally or unintentionally attract external prewar support for its government from oil-importing states. That is, as a state exports oil to more states, more oil-importing states will be willing to support its government. The number of an oil-exporting state’s oil trade partners is identical to the total number of its oil export ties in the oil trade network, X, called ‘degree centrality’. Formally, the degree centrality (C_D (i)) is calculated by the following formula:

C_{D} (i) = \frac{1}{n - 1} \sum_{j = 1}^{n} a_{ij} (i \neq j)

where a_ij is State i’s oil export tie to State j (a_ij = 1 if i exports oil to j and 0 otherwise), and n is the total number of states in the oil trade network in each year (Borgatti, Everett & Johnson, 2013).⁵ I refer to it as Oil trade partners, and use it to test the second hypothesis (H2).

Third, the break of a state’s oil export ties directly and indirectly affects all other states in the oil trade network, including states that do not import oil from the state. The level of a state’s ability to affect all other states identifies the sum of geodesic distances from the state to all others, defined as number of links in the shortest path between two nodes, called closeness centrality (Borgatti, Everett & Johnson, 2013). For example, if two states directly trade oil with each other, their geodesic distance is 1. If the geodesic distance between State a and State b is 2, State a exports oil to state c, which exports oil to State b. The geodesic distance between i and j is calculated by the following formula:

d (i, j) = \min (a_{i h} + \dots + a_{h j})

where h are intermediary nodes on paths between nodes i and j. The closeness centrality (C_c (i)) is calculated by the following formula:

C_{C} (i) = (n - 1) {[\sum_{j = 1}^{n} d (i, j)]}^{- 1} (i \neq j)

where d(i, j) is the geodesic distance between states i and j. I refer it as Oil export ability, and use it to test the third hypothesis (H3).

However, these three variables may mislead results, because they ignore variation in other components of a state’s oil export. In order to simultaneously examine the three effects of a state’s oil export on external prewar support for its government, I combine them by using closeness centrality in weighted networks (Opsahl, Agneessens & Skvoretz, 2010). This index uses a tuning parameter, α, that weights the shortest paths by the amount of a state’s oil export, and defines the geodesic distance between i and j as

d^{w} (i, j) = \min (\frac{1}{x_{i h}^{α}} + \dots + \frac{1}{x_{h j}^{α}})

where, as before, h represents intermediate nodes. In Equation (5), the value of α must be determined by theory (Kinne, 2012). If α = 0, d^w (i, j) is equal to the minimum number of nodes between i and j, as the geodesic distance calculation from Equation (3). An increase in the value of α favors stronger over weaker paths (Kinne, 2012).⁶ Based on Equation (5), Opsahl, Agneessens & Skvoretz (2010) define closeness centrality in weighted networks as

C_{c}^{w} (i) = (n - 1) {[\sum_{j = 1}^{n} d^{w} (i, j)]}^{- 1} (i \neq j) .

To balance the effects of a state’s oil export on external prewar support for the government, I set α at 0.5. I refer to it as Oil market power, and use it to test the fourth hypothesis (H4).⁷

Finally, although I hypothesize that the structure of the international oil market also affects a state’s oil market power, Oil market power does not include the effect of the oil market structure. In order to combine the effect of a state’s oil export and the effect of the oil market structure on the exporter, I employ the Freeman Centralization index that refers to the extent a network is dominated by a single node (Borgatti, Everett & Johnson, 2013). Freeman Centralization is the sum of differences in degree centrality between the node that has the most ties and all other nodes divided by the sum of such differences in a network of the same size, which a single node dominates, and is calculated by the following formula:

C e n_{t} = \frac{\sum_{i = 1}^{N} C_{D} (P_{*}) - C_{D} (i)}{max \sum_{i = 1}^{N} C_{D} (P_{*}) - C_{D} (i)}

where t is a given year and P_* is the node that has the most ties in a network. In order to test the fifth hypothesis (H5), I calculate Weighted oil market power with the following formula:

C_{c t}^{w} (i) = C_{c}^{w} (i) \times C e n_{t}

Control variables

I employ control variables considered in past studies as important causes of civil war onset to isolate the effects of my primary independent variables on both external support for the government and civil conflict onset. The first control variable is Oil income/capita (log), which measures the natural log of the total crude oil production (metric tons), divided by population and multiplied by the world oil prices expressed in 2013 dollars using the US Energy Information Administration’s dataset (2014) and British Petroleum’s (2014) dataset. Although most prior studies on civil war onset have employed a binary variable for fiscal reliance on oil (e.g. Fearon & Laitin, 2003) or the natural log of oil production (e.g. Collier & Hoeffler, 2004) to test the effect of oil on civil war onset, I argue that their variables may ignore the effect of variations in oil on civil war onset or may miscalculate the value of capturing state or a rebel group’s financial capability obtained by selling oil or booty futures because the variables do not include oil prices.

The second control variable is GDP/capita, which measures the natural log of GDP per capita based on data from Gleditsch (2002). Generally, wealthier states have a lower likelihood of civil war onset, because they have more resources to invest in either repressing or appeasing dissent (Fearon & Laitin, 2003). The third control variable is XPolity, which measures the level of democracy for conflict studies by removing the constituent terms of the index that are endogenous to political violence (Vreeland, 2008). Fourth, I consider factors that offer rebels military advantages over the government by controlling for Mountainous terrain (Fearon & Laitin, 2003), Ethnic and Religious fractionalization (Alesina et al., 2003), and the logged Population size (World Bank, 2013). Finally, I employ two variables, the number of Alliances (Gibler, 2009) and the number of Contiguous states (Stinnett et al., 2002), that could affect oil-importing states’ decisions to support an oil-exporting state’s government.

Results⁸

Oil export and external prewar support for an oil-exporting state’s government

I begin by examining the influence of a state’s oil export on external prewar support for its government in Table II. All models can be interpreted similarly with positive coefficients indicating that external prewar support for a state’s government becomes more likely as the independent variable increases. Each model in Table II includes one independent variable and control variables to examine each hypothesis.

The coefficients of the independent variables in the models in Table II, except Model 3, are positive and statistically significant. These results support the hypotheses that a state’s oil export increases the likelihood of external prewar support for its government. However, empirical results in Model 3 reveal that a state’s indirect oil export ties rarely affect the likelihood of external prewar support for its government.

Beyond statistical significance, I calculate each variable’s marginal effect on the dependent variable in Table II using the Clarify program (King, Tomz & Wittenberg, 2000; Tomz, Wittenberg & King, 2003). The results for these calculations with Model 5 are graphically presented in Figure 1, which displays how we should expect the likelihood of external prewar support for a state’s government to vary when Weighted oil market power or each control variable is allowed to vary from its 25th to its 75th percentile while holding all other variables constant (means). In substantive terms, the effect of a state’s Weighted oil market power on external prewar support for its government is considerable. If a state does not have oil market power, the likelihood of external support for the government side is around .005. However, if a state has .45 Weighted oil market power, such as Equatorial Guinea and Ivory Coast, the likelihood of external prewar support for its government would jump to .006, which represents an increase of around 16.4%. This result supports the fifth hypothesis.

Regarding the control variables, although coefficients of most control variables are not statistically significant, the coefficient of GDP/capita is negative and statistically significant. Specifically, states are around 72.3% (.012–.003) less likely to experience external prewar support for

Table II.

Oil export and external prewar support for the government, 1986–2007

	Model 1	Model 2	Model 3	Model 4	Model 5
	(H1)	(H2)	(H3)	(H4)	(H5)
Oil export (log)	0.189**
	(0.064)
Oil trade partners		0.151**
		(0.056)
Oil export ability			0.703
			(4.419)
Oil market power				0.062*
				(0.025)
Weighted oil market power					0.364*
Weighted oil market power					(0.145)
Oil income/capita (log)	−0.125	−0.049	−0.099	−0.018	−0.009
	(0.103)	(0.123)	(0.110)	(0.111)	(0.110)
GDP/capita (log)	−0.731*	−0.641*	−0.695*	−0.683*	−0.684*
	(0.282)	(0.279)	(0.277)	(0.275)	(0.275)
XPolity	0.014	0.015	0.011	0.016	0.016
XPolity	(0.082)	(0.081)	(0.077)	(0.079)	(0.080)
Mountainous terrain	0.051	0.059	0.056	0.047	0.048
	(0.180)	(0.182)	(0.181)	(0.179)	(0.179)
Ethnic fractionalization	−0.115	−0.041	0.105	0.041	0.041
Ethnic fractionalization	(0.926)	(0.890)	(0.923)	(0.892)	(0.891)
Religious fractionalization	0.898	1.149	0.865	1.128	1.118
	(1.591)	(1.549)	(1.708)	(1.539)	(1.547)
Population (log)	−0.235	−0.186	−0.145	−0.160	−0.158
	(0.199)	(0.205)	(0.194)	(0.203)	(0.201)
Alliances	−0.024	−0.023	−0.021	−0.025	−0.025
	(0.019)	(0.020)	(0.020)	(0.021)	(0.020)
Contiguous states	0.076	0.062	0.100	0.053	0.058
	(0.083)	(0.070)	(0.086)	(0.068)	(0.069)
Constant	3.053	1.848	1.290	2.020	1.974
	(3.360)	(3.450)	(4.671)	(3.438)	(3.422)
N	2,914	2,914	2,914	2,914	2,914
N_States	148	148	148	148	148
Wald chi²	49.59***	69.04***	41.59***	55.74***	56.88***
Hosmer-Lemeshow chi²	4.91	10.63	10.93	12.86	12.78
ROC	0.793	0.787	0.774	0.785	0.785

^† p < .10, *p < .05, **p < .01, ***p < .001 (two-tailed). Cell entries report coefficients and cluster-corrected standard errors (in parentheses) from logistic regressions. Peace years not shown.

their governments as their GDP/capita varies from its 25th to its 75th percentile. This implies that the increase in a state’s capability to invest in either repressing or appeasing dissent discourages third parties from supporting its government because third parties are likely to expect that political instability problems in the state would be resolved by its government.

Finally, I ran tests for model fit. In addition to the common Wald’s chi-squared statistics, which are significant at <.001 for all models, I include Hosmer & Lemeshow (2000) and receiver operating characteristic (ROC) curve analyses (King & Zeng, 2001). The Hosmer-Lemeshow test divides subjects into deciles based on predicted probabilities and then computes a chi-squared test between observed and predicted values of the dependent variables for each group, with the null hypothesis that groups are similar. Each of these tests is statistically insignificant, indicating that the models fit the data well. The ROC curve calculates the true-positive rate against the false-positive rate for all possible

Figure 1.

The effect of weighted oil market power on the probability of external prewar support for an oil-exporting state’s government, 1986–2007: Substantive effects

cutpoints (ranging from 0 to 1). The ROC value of each model ranges from .774 to .793, indicating a fair/good model fit. These results suggest that a state’s oil export should be considered to predict the likelihood of external prewar support for its government.

Oil export and civil conflict onset

Table III presents the estimates of three models of civil war onset, including baseline logit models of civil conflict onset (Models 6 and 7) and a model that tests the conditional hypothesis (H6) (Model 8). All models can be interpreted similarly with positive coefficients indicating that civil conflict onset becomes more likely as an independent variable increases. In Table III, the dependent variable is Onset. Each model in Table III includes independent and control variables to examine the sixth hypothesis (H6).

Model 8 in Table III supports the sixth hypothesis that the effect of a state’s oil market power on civil conflict onset depends upon the presence of external prewar support for its government. Figure 2 reveals that the presence of external prewar support for a state’s government means that the state’s oil market power rarely affects the likelihood of civil conflict onset when its oil market power is higher than 1, such as Indonesia and Qatar. However, if a state does not yet experience external prewar support for its government, the increase in its oil market power would be likely to cause civil conflict onset. This result reveals that external prewar support for an oil-exporting state’s government reduces the likelihood of the bargaining failure between the government and rebels generated by the rebels’ incomplete information about the government’s oil export, and supports the sixth hypothesis.

Regarding the control variables in Model 8, we first see that having an experience with neutral prewar

Table III.

Oil export and onset of civil war, 1986–2007

	Model 6	Model 7	Model 8
	(Full sample)	(Full Sample)	(H6)
Weighted oil market power	0.095	0.095	0.109
Weighted oil market power	(0.111)	(0.110)	(0.109)
Intervention	0.749^†
	(0.423)
Government		0.614	1.482**
		(0.611)	(0.493)
Weighted oil market power ×Government			−0.949*
Weighted oil market power ×Government			(0.481)
Neutral		1.106*	0.896^†
		(0.491)	(0.483)
Rebel		0.258	0.267
		(0.559)	(0.541)
Oil Income/capita (log)	0.059	0.063	0.069
	(0.079)	(0.079)	(0.078)
GDP/capita (log)	−0.405**	−0.388**	−0.387**
	(0.139)	(0.138)	(0.138)
XPolity	0.000	−0.004	−0.003
XPolity	(0.027)	(0.027)	(0.027)
Mountainous terrain	0.042	0.047	0.046
	(0.082)	(0.083)	(0.083)
Ethnic fractionalization	1.287**	1.303**	1.381**
Ethnic fractionalization	(0.485)	(0.486)	(0.492)
Religious fractionalization	−1.242*	−1.307*	−1.430*
	(0.590)	(0.584)	(0.598)
Population (log)	0.206*	0.218*	0.215*
	(0.101)	(0.101)	(0.100)
Alliances	−0.007	−0.008	−0.009
	(0.009)	(0.009)	(0.009)
Contiguous states	0.025	0.024	0.027
	(0.043)	(0.043)	(0.042)
Constant	−1.858	−2.134	−2.198
	(1.405)	(1.391)	(1.389)
N	2,914	2,914	2,914
N_States	148,9	148,9	148,9
Wald chi²	119.5***	129.8***	114.9***
Hosmer-Lemeshow chi²	8.05	9.44	5.07
ROC	0.796	0.800	0.802

^† p < .10, *p < .05, **p < .01, ***p < .001 (two-tailed). Cell entries report coefficients and cluster-corrected standard errors (in parentheses) from logistic regressions. Peace years not shown.

intervention increases the likelihood of civil war by around 161.5% (.023–.061). This reveals that although third parties may neutrally intervene in a state to prevent civil conflict, the neutral prewar intervention may increase the likelihood of civil conflict onset. Prior studies on the effect of third-party intervention on civil war duration have argued that third parties as veto players are likely to reduce the bargaining range and aggravate information problems (Cunningham, 2006) because third parties, who bear lower costs of fighting and anticipate

Figure 2.

Conditional marginal effects of weighted oil market power on civil conflict with 95% CIs, 1986–2007

gaining less benefit from negotiation than the internal actors, generally have less incentive to cease civil war and negotiate than internal actors (Cunningham, 2010). This implies that neutral prewar intervention is likely to introduce veto players who can reduce the prewar bargaining range and causes information problems rather than to reduce the likelihood of civil conflict onset. Second, in Model 7, coefficients of Ethnic fractionalization and Population support the arguments of previous studies that a higher level of ethnic fractionalization and a larger size of population increase the number of potential recruits to an insurgency and, thus, increase the likelihood of civil conflict onset (Fearon & Laitin, 2003). States are around 100.3% (.017–.033) more likely to experience civil conflict onset as Ethnic fractionalization varies from its 25th to its 75th percentile. A move from the 25th to the 75th percentile (8.20–10.03, ln values) in Population also increases the likelihood of civil war by around 46.8% (.019–.028). However, the coefficient of Religious fractionalization does not support the argument of prior studies that a higher level of religious fractionalization increases the likelihood of civil war onset (Fearon & Laitin, 2003). Specifically, states are around 38.6% (.030–.018) less likely to experience civil conflict onset as Religious fractionalization varies from its 25th to its 75th percentile. Other control variables are not statistically significant. Finally, each model’s Hosmer-Lemeshow chi-squared values in Table III are statistically insignificant, indicating that the models fit the data well, and their ROC values range from .796 to .802, indicating a fair/good model fit. This suggests that a state’s oil export and external support for its government should be considered to predict the likelihood of civil conflict onset.

Conclusion

This study explores the effect of a state’s oil export on external prewar support for its government and civil conflict onset. The literature on civil war onset has rarely dealt with oil export as a strategic tool that affects oil-importing states’ decisionmaking. I argue that the increase in a state’s oil market power is likely to attract external prewar support for its government because oil-importing states try to avoid the break of their oil trade ties caused by civil war onset in the state. I also argue that the increase in a state’s oil market power increases the likelihood of civil conflict onset because rebels are less likely to have complete information about the government’s oil export and, thus, are less likely to accurately calculate the likelihood of external prewar support for the government attracted by its oil export. However, because external prewar support for an oil-exporting state’s government gives to rebels the information about the possibility that the government’s oil export attracts external support for it, both sides are less likely to fail to find an acceptable bargaining range and, thus, the government’s oil export is less likely to affect the likelihood of civil conflict. In order to examine these arguments, I estimate each state’s oil market power with network analysis, and the empirical results support the arguments.

This research provides three implications. First, the effect of oil on civil conflict is more complicated than prior studies have argued. Although prior studies have focused on the effect of oil on domestic actors, including the government and rebels, this study reveals that oil can also affect external actors. This reveals why empirical results of prior studies have not consistently revealed the effect of oil on civil war onset. This implies that we should consider the effect of oil on both domestic and international actors. Second, this research reveals that although international trade can affect conflict onset, the effect of trade on conflict onset depends on which product a state exports to and/or imports from other states. I argue that the structure of the international oil market and the importance of oil as a primary energy source increase the ability of an oil-exporting state to attract external support for its government. However, if a state exports strategically or economically less important products, such as toys, to other states, its trade ties would rarely cause high exit costs or provide leverage over its trade partners. Thus, to analyze the effect of trade on conflict, we should focus on what a state exports to and/or imports from other states. Finally, this study suggests that energy policies are important factors in international society. An oil-exporting state’s ability to attract external support is derived from the exporter-favored structure of the international oil market and the importance of oil as a primary energy source. This implies that an oil-exporting state’s ability to attract external support would be reduced by oil-importing states’ renewable energy development policies that allow the importers to rely less on the international oil market and reduce the importance of oil as a primary energy source.

Footnotes

Replication data

The dataset and the do-file for the empirical analysis in this article and the Online appendix can be found at http://www.prio.org/jpr/datasets and .

Acknowledgements

The author wishes to thank Clayton Thyne, Daniel Morey, Emily Beaulieu, Tyson Chatagnier, and three anonymous reviewers for their helpful comments.

Notes

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Supplementary Material

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0.00 MB

Oil export,external prewar support for the government,and civil conflict onset

Abstract

Keywords

Introduction

Oil and civil war onset

Prewar intervention and civil conflict

Oil export and external prewar support for the government

Oil export, external prewar support for the government, and civil conflict onset

Research design

Oil trade network and network centrality 3

Control variables

Results 8

Oil export and external prewar support for an oil-exporting state’s government

Oil export and civil conflict onset

Conclusion

Footnotes

Replication data

Acknowledgements

Notes

References

Supplementary Material

Oil trade network and network centrality³

Results⁸