Horizontal Inequality, Organizational Structure and Conflict Duration: A survival analysis of civil wars involving excluded ethnic groups

Horizontal Inequality, Organizational Structure and Conflict Duration

A survival analysis of civil wars involving excluded ethnic groups

Linn Kristin Sande

Master’s in Peace and Conflict Studies Department of Political Science

University of Oslo

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Horizontal Inequality, Organizational Structure and Conflict Duration

A survival analysis of civil wars involving excluded ethnic groups

Linn Kristin Sande

Spring 2016

© Linn Kristin Sande 2016

Horizontal Inequality, Organizational Structure and Conflict Duration Word count: 43511

Linn Kristin Sande http://www.duo.uio.no/

Print: Weberg Printshop, Oslo

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Abstract

Why do some civil wars last for decades while other end after a few weeks? This is a question that has largely been ignored in the civil war literature. The majority of studies on internal conflict focus on conflict onset, affording less attention to the factors that sustain conflict. In an attempt to contribute to the body of quantitative research on conflict duration, I posit that horizontal inequality mobilization and the organizational structure of rebel organizations sustain civil war. Firstly, I claim that rebel organizations mobilized by horizontal inequality are defined by substantial commitment problems that prevent the parties from reaching a peace agreement. Secondly, I claim that the organizational structure of a rebel group determines whether or not it is able to credibly commit to a peace agreement, as a fragmented rebel organization is unable to commit its entire organization. I consequently use bargaining theory to explain sustained conflict. Thirdly, I claim that the effect of horizontal inequality mobilization on sustaining conflict is interdependent on the organizational structure of the rebel group. Sustained conflict is not solely explained by bargaining problems, but also by the rebel organization’s ability to retain enough recruits to fight the government. Horizontal inequality creates strong social ties within the potential recruitment pool that are likely to affect the cohesion of the resulting rebel organization. The mobilizing effect of horizontal inequality might therefore be institutionalized within the organizational structure of the rebel group.

Utilizing data on 267 conflict-dyads from 1946 to 2005, I conduct several survival analyses to test these claims empirically. I find that horizontal inequality mobilization decreases the risk of conflict termination, and that strong central control increases the risk of conflict termination. Furthermore, I find that the effect of horizontal inequality mobilization is dependent on the organizational structure of the rebel group. The introduction of the interaction term renders the horizontal inequality variable insignificant, implying that it is the organizational structure of a rebel organization, not the grievance motivation of its recruits, that sustains the group and consequently allows it to continue fighting. These findings highlight the importance of ethnic discrimination and the characteristics of rebel organizations when investigating protracted conflicts. Moreover, they posit that organizational structure is a particularly important factor when explaining rebel groups’ ability to retain recruits.

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Acknowledgements

During the process of writing this thesis, it sometimes felt like a very lonesome project.

However, the final result as it stands today would not have come to be without the many people that have helped and supported me. First, a huge thanks goes out to my supervisors, Scott Gates and Håvard Mokleiv Nygård, without whose knowledge and enthusiasm this thesis would have looked very different. Your many comments and suggestions helped me improve my thoughts and ideas, guiding me towards the final result we see today. Second, I would like to thank Håvard Strand, Scott Gates and Håvard Mokleiv Nygård for hiring me as their research assistant. Working on your projects helped me improve my Stata skills and this thesis would not have gone as smoothly without the many hours spent studying your do-files.

Third, a huge thanks goes out to my friend and roommate Vårin Alme, for being my pillar throughout this process. Thank you for correcting my spelling errors, giving me advice, and ensuring that I remember to eat and take breaks. Fourth, I would like to thank the other PECOS students writing their theses in the 9^th floor reading room for much-needed coffee breaks and solidarity during this process. Fifth, I would like to thank all my friends who listened to me complain about my thesis, or just provided some long sought-after time-outs over a beer or a glass of wine. Finally, a huge thanks goes out to my family for having been so invested in my education from the start. Your support has meant a great deal throughout this process, and I am very lucky to have you all.

All remaining errors in this thesis are my responsibility alone.

Word count: 43511 Linn Kristin Sande Oslo, 22.05.2016

Replication data for the analysis is made available to the public.¹The dataset and do-files from STATA can also be provided upon request.

Contact: linn.k.sande@gmail.com

1 https://www.dropbox.com/sh/hzagz1dwlaytnds/AAAQTWPxUOl-_OXvSeu3z3Lda?dl=0

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Contents

List of Figures…...……...………XII List of Tables..………XIII-XV

1   Introduction ... 1  

1.1 Theoretical argument ... 4  

1.2 Findings ... 6  

1.3 Central concepts ... 6  

1.3.1 Conflict ... 7  

1.3.2 Rebel organization ... 7  

1.3.3 Horizontal inequality mobilization ... 8  

1.3.4 Organizational structure ... 8  

1.4 Structure ... 9  

2   Literature Review ... 10  

2.1 Horizontal inequality thesis ... 10  

3.2 Organizational theory and conflict duration ... 14  

2.2.1 Cross-conflict analyses of rebel organizations ... 17  

2.3 My contribution ... 20  

3   Theoretical Framework ... 22  

3.1 Bargaining theory and conflict duration ... 23  

3.2 Horizontal inequality and bargaining ... 25  

3.2.1 Identity formation ... 25  

3.2.2 Mobilization ... 27  

3.3 Organizational structure and bargaining ... 32  

3.3.1 Factions ... 33  

3.4 Interdependent relationship ... 38  

3.5 Summary ... 43  

4   Research Design ... 45  

4.1 Why a quantitative design? ... 45  

4.2 Statistical model ... 46  

4.2.1 Cox proportional hazard model ... 47  

5   Data and Unit of Analysis ... 50  

5.1 Dataset and units of analysis ... 50  

5.2 Operationalizing concepts ... 51  

5.2.1 Dependent variable: Time to conflict termination ... 51  

5.2.2 Independent variables: ... 54  

Horizontal inequality mobilization ... 54  

Organizational structure ... 57  

Combined horizontal inequality and organization ... 60  

Control variables ... 61  

5.3 Methodological challenges ... 66  

5.3.1 Unmeasured heterogeneity and repeated events ... 66  

5.3.2 Tied failures ... 67  

5.3.3 Proportionality ... 68  

5.3.4 Right-censored observation ... 70  

5.4 Summary: The dataset ... 71  

6   Empirical Analysis ... 72  

6.1 Descriptive statistics ... 72  

6.2 Survival analyses ... 77  

6.2.1 Horizontal inequality mobilization ... 77  

6.2.2 Central control ... 81  

6.2.3 Interaction effect of horizontal inequality and central control ... 84  

6.3 Findings ... 89  

7   Model Robustness ... 91  

7.1 Alternative estimation method ... 91  

7.2 Jackknife estimations ... 95  

7.3 Proportionality assumption ... 97  

7.4 Omitted variable bias ... 105  

7.5 Including missing values on central control ... 108  

7.6 Including missing values on natural resources ... 111  

7.7 Further tests ... 114  

8   Conclusion ... 116  

8.1 Main findings ... 116  

8.2 Implications and future research ... 118  

8.3 Weaknesses ... 121  

8.4 Concluding remarks ... 122  

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9   Bibliography ... 124  

Appendix A ... 135  

Appendix B ... 139  

Appendix C ... 144  

List of Figures

Figure 3.1: Sustained conflict………...…. 23

Figure 3.2: Horizontal inequality and sustained conflict………...……….… 31

Figure 3.3: Bargaining with cohesive rebel organization………..…. 35

Figure 3.4: Bargaining with factionalized rebel organization………..…… 37

Figure 3.5: Organizational structure and sustained conflict……….………... 38

Figure 3.6: Interaction between horizontal inequality and organizational structure………… 43

Figure 5.1: Battle-deaths per year under 100……….………... 53

Figure 6.1: Kaplan-Meier survival curve for excluded……….... 74

Figure 6.2: Kaplan-Meier survival curve for strength of central control………... 75

Figure 6.3: Kaplan-Meier survival curve for strong central control……….. 77

Figure A.1: Distribution of best estimate battle-deaths per year………..………..135

Figure A.2 Log-log test of coups………136

Figure A.3: Kaplan-Meier observed vs. predicted curves for excluded………..137

Figure A.4: Kaplan-Meier observed vs. predicted curves for strength of central control...138

Figure A.5: Kaplan-Meier observed vs. predicted curves for strong central control……...138

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List of Tables

Table 5.1: Descriptive statistics………... 71

Table 6.1: Incident rate by excluded……….... 73

Table 6.2: Incident rate by strength of central control………..….. 75

Table 6.3: Incident rate by strong central control………... 76

Table 6.4: Cox proportional hazard models……… 79

Table 6.5: Cox proportional hazard model with interaction term………...…… 87

Table 6.6: Tabulating excluded against central control……….……….… 88

Table 7.1: Weibull models clustered on conflict ID………...…. 93

Table 7.2: Jackknife and Bootstrap test on model 4 and 7……….. 96

Table 7.3: Proportional hazard test of model 4………..…….. 98

Table 7.4: Model 3, 4 and 7 tested for time-dependent territorial control interaction…….. 100

Table 7.5: Proportional hazard test of model 13……….... 101

Table 7.6: Link-test of model 13……… 102

Table 7.7: Excluded tabulated for missing values on central control………... 109

Table 7.8: Excluded tabulated by central control if natural resources are missing……... 111

Table A.1: St description of dataset………... 135

Table A.2: Proportional hazard test of unstratified model 1……….. 136

Table A.3: Proportional hazard test of stratified model 1……….. 137

Table B.1: Long-rank test of excluded………..…. 139

Table B.2: Log-rank test of strength of central control………….………...……. 139

Table B.3: Long-rank test of moderate central control.……….………...… 140

Table B.4: Log-rank test of strong central control…….……….. 140

Table B.5: Model 1 unrestricted by missing values on central control………. 141

Table B.6: Link-test of model 1………. 141

Table B.7: Link-test of model 2………. 142

Table B.8: Link-test of model 3………. 142

Table B.9: Link-test of model 4……….… 142

Table B.10: Correlation matrix of model 3………..….. 142

Table B.11: Correlation matrix of model 4……… 143

Table B.12: Wald test of model 4………..…… 143

Table C.1: Alternative estimation methods: Exponential, Log-normal and Log-logistic….. 145

Table C.2: Models with excluded and parity interaction terms with time……….… 146

Table C.3: Proportional hazard test for Model C.4……… 147

Table C.4: Proportional hazard test for Model C.5……… 147

Table C.5: Models controlling for omitted variable bias………...…… 148

Table C.6: Models controlling model 7 for omitted variable bias………. 149

Table C.7: Models controlling for omitted variable bias.………..… 150

Table C.8: Descriptive statistics for omitted variables………..… 151

Table C.9: Proportional hazard test for Model C.17……….. 151

Table C.10: Models with dummy for missing values on central control……….. 152

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Table C.11: Proportional hazard test for Model C.19……… 153

Table C.12: Proportional hazard test for Model C.20……… 153

Table C.13: Models with dummy for missing values on natural resources………….……. 154

Table C.14: Proportional hazard test for Model C.23……… 155

Table C.15: Proportional hazard test for Model C.24……… 155

Table C.16: Proportional hazard test for Model C.25……… 156

Table C.17: Proportional hazard test for Model C.26………...…. 156

Table C.18: Models with dummy for missing values on natural resources……….. 157

1

1 Introduction

The conflict between the Karen National Union (KNU) and the government in Myanmar plagued the country for over sixty years before the signing of the peace treaty in 2012. The Second Sudanese Civil War is another example of an internal conflict that endured for several decades before it finally ended with a peace agreement in 2005 and the eventual secession of South Sudan in 2011 (Ottaway and El-Sadany 2012:1). Conversely, the conflict between the Janathā Vimukthi Peramuṇa (JVP) and the Sri Lankan government in both 1971 and 1989 lasted under a year. Also the conflict between the Socialist and Revolutionary Labour Party (SRLP) and the Gambian government had a short duration, ending after only one week (Cunningham 2011b:260). There are consequently huge variations in the duration of civil wars.

Conflict is often perceived in all or nothing terms, whereby episodes of war and peace are viewed as distinct phenomena. As illustrated by the examples above, however, conflicts differ greatly from one another. The surge in annual conflict episodes in the world after 1950 was not due to increased conflict onsets, but rather the increased duration of civil wars (Fearon and Laitin 2003:78; Hegre 2004:244). Conflicts lasted for a longer time period, thus leading to an accumulation of conflicts that increased the proportion of countries experiencing civil war in any given year. Civil wars now last about four times as long as interstate wars, suggesting that civil wars have become exceptionally protracted (Brandt et al. 2008:415). The long duration of civil war has significant repercussions, as sustained conflict also means even greater numbers of deaths and large humanitarian crises (Doocy et al. 2010:274). While the annual number of battle-deaths in civil wars is substantially lower than those of interstate wars, the protracted nature of these conflicts leads to a cumulative death toll that greatly exceeds that of interstate wars (Brandt et al. 2008:416). Moreover, civil wars occur disproportionally in poor countries, meaning that its terrible ramifications affect already vulnerable populations (Hegre 2013:1). An important step towards establishing a more peaceful world is consequently not only to understand why there is war, but also to understand why war endures.

Conflicts between different ethnic groups appear to last particularly long. Denny and Walter (2014:201) found that ethnic conflicts on average last 5 years longer than non-ethnic conflicts.

This indicates that conflicts between different ethnic groups are even more costly and destructive than other civil wars. This relationship is mirrored in the conflicts listed above, where the protracted conflicts had an ethnic dimension while the shorter conflicts did not.

Yet, the conflict literature is still inconclusive with regard to the causal relationship between ethnic heterogeneity and conflict duration. Moreover, there is no commonly accepted theory explaining why ethnic conflicts should become more protracted than other conflicts. The relationship between ethnic identity and sustained conflicts is consequently of particular interest when studying conflict duration.

In this thesis, I set out to investigate the relationship between horizontal inequality mobilization and sustained conflict. The horizontal inequality thesis posits that it is not ethnicity per se that causes civil war onset, but rather inequality experienced in relation to one’s group-identity. Group inequality amplifies the us-them divide within the country, and provides motivation to challenge the government. Moreover, the shared identity contributes a pre-existing recruitment pool of potential rebels (Cederman, Weidman and Gleditisch 2011:482). As such, the horizontal inequality thesis lays out the mechanisms that motivate and enable ethnic groups to form rebel organizations. While significant research has been conducted on the mobilizing effect of horizontal inequality (e.g. Østby 2008, Buhaug, Cederman and Gleditsch 2014), less research has focused on the impact of these mobilizing factors after initial recruitment. We therefore know little about the rebel organization that emerges as a result of horizontal inequality and how the mobilization of excluded ethnic groups affects conflict dynamics. Consequently, further research on horizontal inequality is warranted.

My point of departure for this investigation is the theoretical framework presented by Cederman, Gleditsch and Buhaug (2013:175), who argue that

the most remarkable feature of the recent literature on conflict duration is how many authors provide accounts for factors influencing conflict duration that are strikingly different from their suggested explanations for conflict onset.

This is an interesting observation, as the factors that first mobilize rebels to fight against the regime are likely to continue to influence their motivation for remaining within the rebel organization. Simply put, it is logical to expect that the factors that originally recruit rebels to

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take part in an insurgent group affect the organization that emerges. Such a connection between mobilization and the ensuing rebel organization should especially be seen when the rebel group recruits from discriminated cultural groups. These recruits share common grievances, history, ethnicity, language, religion and traditions. Such shared motivations and social ties are likely to influence the type of organization that emerges, and how it interacts with the government (Staniland 2014:21).

Although the factors that initially mobilized recruits are likely to affect the resulting rebel organization, the organizational structure of the rebel group also plays a significant role.

Horizontal inequality mobilizes recruits with a shared ethnic identity and shared grievances against the government. Nevertheless, the ability of these factors to sustain the rebel organization is likely to vary depending on how well the rebel organization is structured. If a rebel organization is badly organized and is unable to effectively target the government, initially motivated recruits might become disillusioned with the rebel organization. Research on organizational structure has revealed that the structure of the insurgent group has clear implications for the recruits within the organization, and for the overall dynamics of the conflict (e.g. Humphreys and Weinstein 2006; Staniland 2014). In order to understand the mechanisms through which horizontal inequality sustains rebel organizations, and thus conflict, we must therefore also look at the organizational structure of the rebel organization.

The research question that guides this thesis is:

Research question: How do horizontal inequality mobilization and the organizational structure of the rebel group sustain civil war?

I apply an organizational perspective when theorizing about the duration of conflict. Civil wars are fought between the government army and a rebel organization. To explain how civil war is sustained, we must therefore look at the factors that sustain the rebel organization. In relation to horizontal inequality mobilization, I theorize about the effect this mobilization process has on the rebel organization, and how this influences its interactions with the government. As an extension of this perspective, I also argue that the organizational structure of the rebel group in itself plays an important part in sustaining conflict. Recent organizational studies of rebel groups have uncovered that rebel organizations vary greatly in how cohesively they are organized (Staniland 2014; Seymour, Bakke and Cunningham

2016:4). While some rebel organizations have a clear command structure and a leader that controls the organization, other rebel groups are widely divided and uncoordinated. This diversity in organizational structure suggests that rebel organizations differ in their ability to control recruits, and in how capable they are in carrying out strategies and effectively fighting the government (Johnston 2008:109). These factors are likely to affect the motivation of rebels to remain within a rebel organization. The theoretical framework presented in this thesis thus combines mobilizing factors with organizational theory. By doing so, I attempt to connect the mobilizing factors that lead to the onset of conflict with the resulting dynamics of the war.

1.1 Theoretical argument

I use bargaining theory as a theoretical tool to explain how horizontal inequality and organizational structure influence the peaceful settlement of conflict. Bargaining theory posits that conflict continuation is explained by bargaining problems that prevent the actors from reaching a negotiated agreement. In order to theorize about the effect of horizontal inequality and organizational structure on sustaining conflict, I present a theoretical framework that looks at how these factors affect the bargaining position of a rebel organization.

Looking at the mechanisms though which horizontal inequality mobilize rebels for violent opposition, it is likely that these rebel organizations are defined by commitment issues. The horizontal inequality thesis contends that rebels are mobilized in response to patterns of exclusion, as discrimination against their ethnic groups makes their cultural identity politically relevant. This identity formation is conducted in relation to the governing “out- group”, thus establishing an us-vs.-them mentality within the rebel organization that has potential of creating commitment problems in their peace negotiations with the government.

Commitment problems prevent the bargaining partners from reaching a negotiated agreement, as they are uncertain about the credibility of the other party. As such, conflict is allowed to endure. The first hypothesis in this thesis is: Horizontal inequality creates commitment problems that prevent the rebel group from reaching a negotiated peace agreement.

Motivational factors do not exist in a vacuum. Recent insights from organizational theory suggest that the organizational structure of a rebel organization plays an integral part in

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determining the ability of rebel organizations to overcome commitment problems (Pearlman and Cunningham 2012). Rebel organizations must be capable of credibly committing their entire group to a peaceful settlement in order for the conflict parties to reach a negotiated agreement. A rebel group with a cohesive organizational structure is better positioned to make such a commitment, as the organizational structure allows the leadership tight control over the recruits. Fragmented rebel organizations, on the other hand, are less credible bargaining partners. The organizational structure of the group does not allow the leaders enough control over their recruits to credibly commit the entire organization to non-violence. As such, the conflict parties are prevented from signing and upholding a peace agreement. The second hypothesis in this thesis is: Strong central control helps rebel organizations overcome commitment problems and reach a negotiated peace agreement.

In order for the factors listed above to sustain conflict, the rebel organization must be able to retain its recruits. Conflict is only sustained as long as both the parties are able to militarily engage each other. This means that commitment issues are unable to sustain conflict if the rebel organization disintegrates, implying that horizontal inequality is only able to sustain conflict as long as it also affects a rebel organization’s ability to retain recruits. Horizontal inequality constructs a crucial identity within the discriminated ethnic group, meaning that these recruits gain particularly large solidarity rewards simply from participating in the rebel organization. As such, horizontal inequality should motivate recruits to remain within an insurgent group. Yet, the ties between recruits and rebel leaders before the initial mobilization of a rebel group are likely to affect the structure of the ensuing organization (Staniland 2014).

This suggests that the strong kinship ties within the discriminated ethnic group is institutionalized into the organizational structure of a rebel organization. The mobilizing effect of horizontal inequality might consequently disappear once the institutional organization of the rebel group has been cemented, as these ties are now captured within the organizational structure of the group. The final hypothesis in this thesis is: The effect of horizontal inequality on sustaining conflict is interdependent on the organizational structure of the rebel organization.

This thesis consequently investigates the effect recruiting from an excluded ethnic group have on sustaining conflict. More precisely, it develops and tests hypotheses about the causal relationship between horizontal inequality mobilization, organizational structure, and conflict

duration. These hypotheses are systematically investigated through a large-N study, using data on 267 conflict-dyads between 1946 and 2005. The scope of this thesis is clearly limited by the theoretical framework guiding the analysis. The level of analysis is the rebel organization, and the theory and analysis therefore focus exclusively on characteristics of rebel organizations and how these characteristics affect bargaining problems and the retaining of recruits. By doing so, this thesis aspires to test whether a fruitful explanatory factor of conflict onset also has explanatory value in relation to sustained conflict.

1.2 Findings

In my empirical analysis, I find significant support for all three hypotheses. Firstly, horizontal inequality mobilization significantly decreases the hazard of conflict termination. This supports the argument that horizontal inequality prevents the conflict parties from reaching a peaceful settlement, due to commitment problems. Secondly, strong central control is found to significantly increase the hazard of conflict termination. This is also in line with the theory, implying that cohesive rebel organizations are better positioned to overcome commitment problems and reach a negotiated agreement. The direction and significance level of both of these explanatory factors are consequently in line with the hypotheses.

Finally, the results reveal that the inclusion of an interaction term between horizontal inequality and strong central control renders horizontal inequality an insignificant explanatory variable of sustained conflict. Strong central control, however, remains positive and significant. This suggests that it is the organizational structure of cohesive rebel organizations, not grievance motivation, which retains recruits within the organization. Horizontal inequality is consequently not sufficient to retain recruits within a rebel organization after initial mobilization.

1.3 Central concepts

To facilitate reading, I will clarify the main concepts of this thesis. These concepts include conflict, rebel organization, horizontal inequality mobilization and organizational structure.

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1.3.1 Conflict

The substantial focus of this investigation is the duration of conflict. Here, I will use the terms conflict, internal conflict, civil war and intrastate war interchangeably. Civil wars are defined by the fact that they take place within one country, where the main conflict actors are the national government and a national opposition movement.² The main defining aspect of civil war is therefore that it is constricted to the territory of a sovereign state, both in terms of location and in terms of actors (Sambanis 2004:816). Civil wars are distinct from interstate wars and colonial wars, as these conflicts do not meet the requirement of internality. Civil wars are further defined by violence, where both conflict actors must exercise effective resistance (Sambanis 2004:816). Internal conflicts are restricted to only include violent episodes where both actors commit violent actions against the other party, excluding one- sided violence such as genocides or politicide. Quantitative coding of conflict involves a numeric battle-deaths per year threshold that a violent episode must pass in order to be defined as a conflict. In this paper, this threshold is sat at 25 annual battle-deaths; in chapter 5 this threshold is discussed in more detail. Lastly, civil wars are distinguished from other types of violence by the fact that it must be motivated by an incompatibility between the government and the rebel organization over government, territory or both (Gleditsch et al.

2002:619). As such, the violence is a continuation of politics using non-conventional methods, where the goal of the opposition movement is some form of political change.

Conflict duration is then the period of time a conflict lasts, from onset to termination. Dating the exact time a conflict starts or terminates is a definition issue, where different researchers use different criteria. In this paper, conflict duration is coded based on the Uppsala criteria, and I will explain this operationalization more thoroughly in chapter 5.

1.3.2 Rebel organization

Based on the Uppsala criteria, a rebel organization is defined as a formally organized opposition group that uses violence to address a political dispute with the government. In order for a rebel group to be formally organized, it must have announced a name for its group

2 Civil wars can contain more than two conflict actors. However, as the focus of this thesis is dyadic conflict between the government and one rebel organization I simplify the definition to match this focus.

and stated its incompatibility with the government. Moreover, the violence must involve

“consciously conducted and planned political campaigns rather than spontaneous violence”

(Themnér 2013:2). The term rebel organization is thus a wide concept that captures all organized opposition movements that use violence as a political tool to achieve their ambitions. Throughout the paper, I use the terms rebel organization, rebel group, opposition group and insurgent group interchangeably.

1.3.3 Horizontal inequality mobilization

Horizontal inequality refers to economic, political and social inequality between cultural groups within a country. Stewart (2002:2) defines cultural groups as relatively constant identities that are meaningful to its members, encompassing all identity-groups that are based around a shared ethnicity, religion or caste. In this thesis, I narrow down the scope of horizontal inequality in order to better allow for quantitative analysis. Ethnicity is a particularly important identity-group in terms of political mobilization (Posner 2004;

Wimmer, Cederman and Min 2009). Moreover, conflict analyses have found that ethnic conflicts have a tendency to become protracted (Denny and Walter 2014:201), suggesting that ethnic identity-groups are of particular interest within conflict duration studies. In this paper, horizontal inequality is therefore limited to encompass inequality distributed in terms of ethnic identity-groups. The concept horizontal inequality mobilization then refers to the act of being mobilized to join a rebel organization by horizontal inequality, and rebel organizations mobilized by horizontal inequality refers to rebel organizations that consist of these recruits.

In chapter 3 and 5, this concept is further expanded upon.

1.3.4 Organizational structure

Organizational structure is a diffuse term that can be broken down into many components (see Sinno 2008:23-45). In this thesis, organizational structure refers to the degree of control the leadership has over the rebels and factions within a rebel organization. A cohesive rebel organization then denotes an insurgent group that is tightly knit and where the leadership has control over the recruits and the factions within the organization. Conversely, a fragmented or fractured rebel organization denotes an insurgent group where the leadership is not in control

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of the factions within the organization. In chapter 3 and 5, this concept is discussed in more detail.

1.4 Structure

This thesis is divided into eight chapters. In Chapter Two, I present a brief summary of the literature on horizontal inequality and organizational theory to locate my thesis within a theoretical dialogue and to identify the gaps within these literatures with regard to my research. In Chapter Three, the theoretical framework is presented. I use bargaining theory as a theoretical tool to explain how horizontal inequality and organizational structure sustain conflict, while arguing that these factors are only able to sustain conflict if they also sustain the rebel organization. In Chapter Four, I present the research design utilized to answer my research question. This thesis is a quantitative study, and I therefore present the benefits of a quantitative research design and specifically the Cox proportional hazard model when investigating conflict duration. In Chapter Five, I then present the dataset I use to empirically test my hypotheses. Here, I discuss the operationalizations of the dependent variable and the main explanatory factors, as well as introducing the control variables and discussing potential weaknesses with the data and the research design. In Chapter Six, I present the empirical analysis obtained from the Cox proportional hazard models. Based on the findings in these models, I make inferences about my theoretical argument and tentatively conclude that there is empirical support for my hypotheses. In Chapter Seven, I then conduct several robustness tests on the original models in order to assert the validity of my findings. Finally, in Chapter Eight I present the conclusion of my thesis. Moreover, I discuss the implications of these findings and discuss the strengths and weaknesses of the analysis.

2 Literature Review

Research on conflict duration has grown considerably in the last decade (e.g. Hegre 2004;

Collier, Hoeffler and Söderbom 2004; Lujala 2010). Yet, the literature on conflict duration is still sparse in comparison with the conflict onset literature, suggesting that further research is still needed. In this chapter, I look into the existing literature on horizontal inequality and organizational theory. This is done in order to identify the relevant contributions within both these literatures that I rest my theoretical argument on, while pointing out the gaps that needs to be addressed. To do so, I divide the literature review into two parts. Firstly, I present the existing literature on horizontal inequality. Here, I present the theoretical framework by Cederman, Gleditsch and Buhaug (2013), as this is the framework that I aim to add to.

Secondly, I present some main contributions within organizational theory in relation to rebel organizations. On the basis of this, I explain why organizational structure is an important explanatory factor of sustained conflict and why the inclusion of this factor is an improvement of the existing framework theorizing about excluded ethnic groups and conflict duration.

2.1 Horizontal inequality thesis

The argument that inequality experienced in relation to ethnic identity mobilizes potential rebels for violent conflict has existed within the conflict literature for decades. Cohen (1974:94), for instance, argued that ethnic conflict is related to the distribution of power within a country, suggesting that political motivation is crucial for ethnic identity to be a mobilizing factor for civil war. Gurr’s (1993) minorities-at-risk theory also follows this logic, arguing that ethnic minorities are at risk of mobilizing for violent conflict if they are politically motivated by grievances. Yet, much of the quantitative analyses of ethnicity as an explanatory factor of conflict have solely focused on ethnic fragmentation. Political motivation has thus been overlooked in many of the studies that conclude that ethnicity has no explanatory power in relation to civil war outbreak (see Fearon and Laitin 2003; Collier and Hoeffler 2004).

The horizontal inequality thesis builds further on the argument that political motivation is a crucial prerequisite for ethnic mobilization. In a nutshell, the thesis argues that group-level inequality mobilizes people for violent opposition, as their group identity is politicised by

11 discriminatory policies. Shared grievances then reinforce group-identity, transforming it into a crucial identity³ for its members (Stewart, Brown and Mancini 2005:9). When inequality coincides with group cleavages, group-identity can be used as a mobilizing agent for rebel recruitment. The horizontal inequality thesis thus combines social identity theory and relative deprivation theory, claiming that when these factors combine, the likelihood of violent mobilization increases (Østby 2011:31). Stewart (2000, 2002, 2008) first presented this argument in a series of qualitative studies, supporting her argument with examples from case studies. The theory has also gained support within the quantitative literature, where several researchers have established a significant causal relationship between horizontal inequality and conflict onset (Østby 2008, 2011; Østby, Nordås and Rød 2009; Gubler and Selway 2012;

Buhaug, Cederman and Gleditsch 2013, 2014). For instance, Buhaug, Cederman and Gleditsch (2014) found that horizontal inequality variables are better predictors of conflict onset than vertical measures of both ethnic fragmentation and inequality. There is thus strong empirical support for the argument that ethnic conflicts are motivated by political and economic inequality experienced in relation to group-identity.

While the connection between horizontal inequality and rebel mobilization has gained substantial support within conflict literature, there is almost no research on how these factors affect the dynamics of conflict after initial mobilization. Østby (2011:36) argues that horizontal inequality is especially associated with civil war onset, as it is a mobilization factor. This perspective is also reflected in Stewart’s (2002, 2008) presentation of the horizontal inequality thesis. While she argues that the political context in a country, such as regime type and the level of accommodation from the government, can influence conflict duration, she does not discuss how the mobilization of insurgent groups affects this process.

Yet, research on rebel organizations suggests that the factors that motivate recruits play a significant role in determining the dynamics of internal conflicts (Weinstein 2007; Sanin and Wood 2014). It is therefore possible that the factors that mobilize recruits for violent opposition continue to impact the conflict after the initial outbreak.

Murshed and Gates (2005:129-30) followed this logic as they analysed the effect of horizontal inequality on the intensity of conflict in Nepal. They found that a decrease in the gap in life

3 I define a crucial identity as a relatively constant group-identity that is important enough for its members to be mobilized by it (based on Stewart 2002:6-9).

expectancy, schooling, road density or natural resources between a district and Kathmandu decreased the number of deaths. This suggests that the larger the horizontal inequality, the higher the intensity of the conflict. Murshed and Gates (2005:132) explain this relationship in terms of recruitment, claiming that larger horizontal inequality enables the rebel group to recruit and retain more rebels. Nepal, Bohara and Gawande’s (2011:898) analysis of conflict intensity in Nepal supports this finding, as they also established that larger horizontal inequality leads to more killings. These analyses consequently indicate that horizontal inequality influences rebel organizations after the initial recruitment of rebels.

In relation to conflict duration, there is some support for the argument that horizontal inequality affects recruits after initial mobilization. The two only published analyses are ostensibly by Wucherpfennig, Metternich, Cederman and Gleditsch (2012) and Cederman, Gleditsch and Buhaug (2013), which both indicate that rebel organizations with links to excluded ethnic groups have longer conflict duration than other rebel organizations.⁴ In the book Inequality, Grievances and Civil War, Cederman, Gleditsch and Buhaug (2013:183) present conflict as sequential rounds of bargaining and fighting, whereby conflict is terminated by a negotiated settlement or by victory by either side. Their theoretical argument holds that conflicts with excluded ethnic groups are prone to be protracted, as both negotiated settlement and government victory are less likely in these conflicts. Based on bargaining theory, they argue that both parties are reluctant (and sometimes unable) to grant concessions to the other party, due to fears of further concessions in the future. They thus use commitment issues to explain why the parties are reluctant to end the conflict, and in turn why these conflicts endure.

In terms of government victory, they posit that rebel groups recruiting from excluded ethnic groups are better able to retain their recruits, due to greater cost tolerance and commitment and increased group solidarity (ibid:185).

(T)he features that enable rebel organizations to recruit from excluded ethnic groups also render them harder to defeat for the government… In sum, members of excluded ethnic

4 Several quantitative researchers have looked at the relationship between ethnic fragmentation and conflict duration (Collier, Hoeffler and Söderbom 2004; Montalvo and Reynal-Querol 2010).

However, these are the only quantitative analyses – to my knowledge – that test the relationship between ethnic exclusion and conflict duration.

13 groups are more likely to continue fighting than those who do not suffer from exclusion, which in turn allows rebel organizations to endure (ibid:187, 186).

Continued conflict is thus argued to be the most likely outcome in conflicts including rebel organizations with ties to excluded ethnic groups, as the factors that cause the onset of conflict also make conflict termination difficult. This argument serves as my point of departure, and I build my theoretical framework on the basis of the bargaining framework by Cederman, Gleditisch and Buhaug (2013). Looking at the logic of their argument, however, the mechanisms through which horizontal inequality sustains conflict appear to be oversimplified. Their theoretical argument boils down to the statement that exclusion of an ethnic group explains why conflicts last longer. While it seems likely that ethnically excluded recruits are more motivated to remain within a rebel organization, the theoretical framework fails to properly theorize about how these factors enable the rebel group to retain recruits.

Their theoretical framework therefore opens up for further investigation of the mechanisms through which horizontal inequality sustains conflict.

The theoretical arguments presented by Wucherpfennig et al. (2012) and Cederman, Gleditsch and Buhaug (2013) both build on the assumption that close ethnic ties motivate rebels to remain within a rebel organization. This assumption is widely repeated within the civil war literature, where “(e)thnic nationalism is popularly viewed as the leading source of group cohesion” (Blattman and Miguel 2010:16). Yet, research by Seymour, Bakke and Cunningham (2016:4) indicates that ethno-political rebel organizations have varying group cohesion. Kalyvas (2008:1045) also questions the connection between ethnic identity and cohesion, noting that

even when ethnic divisions cause the eruption of civil war in the first place, these identities do not always remain stable and fixed during the conflict; if they do change, they may soften rather than harden.

The theoretical underpinning of these analyses might consequently build on a faulty assumption of cohesion, suggesting that further research is needed on the potential relationship between horizontal inequality and sustained mobilization.

Cederman, Gleditsch and Buhaug (2013:193) apply an organizational perspective when theorizing on the effect of horizontal inequality on civil war. Yet, their theoretical argument focuses solely on the individual motivation of recruits. While individual motivation to remain within the group is likely to influence the rebel organization and its capabilities, the institutional structure of the rebel organization in itself is also likely to affect the characteristics of the group. The structure of a rebel organization plays a significant role in determining the socialization of rebels, their identification with the rebel group and their ties to the other rebels (Sinno 2008:27). Rebels that were initially highly motivated by horizontal inequality might consequently choose to leave a rebel organization, as in-fighting, distrust or poor leadership decreases their motivation to remain within the group. In this thesis, I suggest that we must study the organizational structure of the rebel organization in order to systematically explore the factors that retain recruits. While building on the theoretical framework by Cederman, Gleditsch and Buhaug (2013), I introduce organizational structure into the framework to gain a fuller understanding of the mechanisms that sustain rebel organizations.

3.2 Organizational theory and conflict duration

Since the late 1970s, several social scientists have held forth organizational structure as an important explanatory factor enabling rebels to overcome the collective action barrier to mobilization (Sinno 2008:9). Charles Tilly (1978) argued that civil war only breaks out when aggrieved groups can mobilize through an organization. Other works highlighting how leadership and traits of organizations enable mobilization and recruitment are Popkin (1979), Taylor (1988) and Laitin (1993). The organizational level has thus been accepted as an important factor when theorizing about conflict onset. More recently, the organizational structure of rebel organizations has also been used in theoretical frameworks explaining the dynamics of civil war (e.g. Weinstein 2007; Johnston 2008; Sinno 2008; Staniland 2010, 2014; Heger, Jung and Wong 2012). These researchers all argue that the characteristics of a rebel organization determine its interactions with the government army:

The organizational theory of group conflict assumes that societal groups, civilizations, religions, and nations do not engage in conflict or strategic interaction – organizations do. Its underlying principle is that the distribution of power within organizations (what we call

15 structure) engaged in conflict creates incentives that motivate the individual behaviour of organizational members in ways that affect each organization’s ability to outlast its rival and to win the conflict (Sinno 2008:87).

The organizational structure of rebel groups has consequently become an increasingly important factor within the literature on civil war dynamics.

Humpreys and Weinstein’s (2006) analysis of civilian abuse is one important contribution to this literature. Studying different fighting groups in Sierra Leone, they found that the main determinant of civilian abuse is the internal structure of rebel organizations. Rebel groups that are unable to police and punish their recruits have higher levels of civilian abuse. Moreover, Humpreys and Weinstein (2006:430) found that once you control for the characteristics of the rebel groups, social ties lose their explanatory value in relation to civilian abuse. This indicates that the organizational structure of a rebel organization plays a greater part than individual feelings and relations in determining the actions of rebels.

Wood’s (2009:152) analysis of wartime rape further supports this finding. Her study of the Liberation Tigers of Tamil Eelam in Sri Lanka suggests that it was the top-down effect of a strictly controlled organizational hierarchy within the rebel group that explained the absence of rape – not the moral norms of the recruits. A strictly controlled organizational structure allowed the leadership to enforce their decisions on the recruits, due to swift and severe punishment for disobedience. These studies consequently indicate that the actions of recruits within a rebel organization are determined by the structure of the rebel group; cohesive rebel organizations are capable of controlling their recruits, due to monitoring and the ability to punish recruits that misbehave. While these are studies of wartime violence, and not conflict duration, they reveal that the organizational structure of a rebel group has great implications for the ability of the organization to motivate recruits to follow orders.

Johnson’s (2008) analysis of rebel organizations’ effectiveness in conflict further suggests that organizational structure affects the interaction between a rebel organization and the government. Comparing and contrasting the organizational structure of LURD and NPFL, he found that the extent to which elites could control subordinates determined the effectiveness of the organization (ibid:125). Looking at the ethnic composition of LURD, he argues that the

group was made cohesive and effective due to a clear leadership structure, rather than shared ethnicity or ideology. The commanders were always close to the subordinates, making it hard for the recruits to disobey orders without being detected (ibid:127). The structure of the rebel organization ensured compliance, resulting in an effective military campaign.

Sinno (2008:23) also highlights the importance of organizational structure in relation to military effectiveness in his book Organizations at War in Afghanistan and Beyond:

Organization allows for coordination among participants, the maintenance of discipline, the minimization of free riding, the efficient mobilization and distribution of resources, the preservation and generation of necessary learning, and the purposeful use of sophisticated strategies to undermine rivals. The way such processes are executed by an organization and its rivals strongly affects their odds of success.

Here, he argues that the organizational structure of rebel organizations affects the behaviour of the recruits, which again influences the performance of the rebel group. The organizational structure sets limitations on the strategies a rebel group can use, as well as the effectiveness of different strategies (ibid:46). Moreover, Sinno’s (ibid:88) theoretical argument holds that the organizational structure of an organization determines the effect of external factors, such as foreign aid and safe havens, in the conflict. The organizational structure of the rebel group is thus a crucial determinant of the dynamics of conflict, as it affects both the capabilities of the rebel group and its effectiveness in utilizing external factors in its favour.

Lastly, Staniland’s (2014:25) book Networks of Rebellion argues that the pre-war ties between recruits and leadership lay the basis for leadership control over the organization. Strong social ties both at the leadership level and between the leadership and the recruits create integrated rebel organizations, and these social ties determine the organizational structure of the organization for the duration of the conflict. Focusing on social ties, Staniland (ibid:41) posits that the level of cohesion within a rebel organization decides its ability to resist counterinsurgency by the government: “Integrated groups are potent foes and only under fairly rare circumstances will counterinsurgency alone induce collapse”. As such, he holds that military victory by the government is particularly hard against cohesive rebel organizations.

17 Literature on rebel organizations and conflict dynamics indicates that the level of cohesion in a rebel organization has clear implications for the conflict, as central control determines the ability of the organization to control its recruits and withstand counterinsurgency.

Organizational structure thus appears to be a crucial factor in sustaining civil war, supporting the argument that this factor must be accounted for when studying sustained conflict. Yet, this literature is still in its infancy. Blattman and Miguel (2010:20) argue that while group cohesion and group socialization have been important within military sociology and history, the literature on rebel organizations within political science still only scratches the surface.

Looking at empirical studies, they argue that this topic “remains one of the most promising and understudied areas in the literature on conflict” (ibid:21). There is consequently a further need for studies on the effect of organizational structure on rebel organizations and civil war dynamics.

2.2.1 Cross-conflict analyses of rebel organizations

In terms of cross-country and cross-conflict statistical analyses, research on organizational structure and conflict dynamics are even further apart. Quantitative civil war analyses are often state-centric, treating the structure of insurgent groups as a given. While conflict is determined by the interaction between two parties – the government and the rebels – this relationship is often overlooked in quantitative analyses. Cunningham, Gleditsch and Salehyan (2009:571-72) address this problem, arguing that while theories on civil war are dyadic in nature, empirical research tends to look exclusively at characteristics of governments. This mismatch is to a large degree due to a lack of data on rebel characteristics.

The introduction of the Non-State Actor (NSA) dataset (Cunningham, Gleditsch and Salehyan 2009) has to a great extent opened up for quantitative analyses of this relationship. The NSA dataset provides cross-conflict dyadic data, allowing for statistical analyses that use rebel organization characteristics as explanatory variables of conflict dynamics. Cunningham, Gleditsch and Salehyan (ibid:573) published the first dyadic analysis of conflict duration. By looking at characteristics of the rebel groups they analysed how relative capabilities affected the bargaining position of rebel groups, finding that rebel groups with strong offensive capabilities relative to the government reach a negotiated agreement faster than rebel groups with weak offensive capabilities.

One area of research that has grown substantially in the last ten years is quantitative analyses of rebel movement fragmentation and conflict duration. Here, researches use bargaining theory to theorize about how the cohesion of rebel movements affects the onset and duration of conflict. Cunningham’s (2006) theory on veto players in civil wars was one of the first contributions to this literature. While he focused on rebel movement⁵ fragmentation, thus focusing on civil wars involving more than one rebel organization, the insights from this analysis lays much of the groundwork for my theoretical arguments on organizational structure and bargaining. Cunningham’s (2006:875) main proposition holds that the more parties are involved in a conflict, the harder it is to resolve through negotiations. Rebel movements can splinter due to different preferences in relation to ideal policy or strategy (ibid:878). These splinter factions have the potential to become veto players in the negotiations with the government if they have different preferences than the original rebel group, are cohesive enough to stick by their demands, and have the ability to continue the conflict unilaterally if the other parties reach an agreement (ibid:879). Based on these characteristics of a veto player, Cunningham (ibid:891) argues that the more veto players there are in a conflict, the longer the duration of the conflict will be. In his analysis, he finds that civil wars with more veto players are much more resistant to resolution. This implies that the fragmentation of rebel movements makes bargaining harder, consequently blocking the peaceful settlement of conflict.

In the wake of this article, several other quantitative researchers have studied the effect of rebel movement fragmentation on civil war (Cunningham 2011a, 2013; Cunningham 2011b;

Pearlman and Cunningham 2012, MacLauchlin and Pearlman 2012). In relation to fragmentation and bargaining, Pearlman (2009:85-86) found that internal contestation over leadership within a rebel movement leads to spoilers in peace negotiations. If there is not an institutionalized leadership structure in a movement, different factions might assert their own position by using violence to spoil peace talks, prolonging the duration of civil war. This is to a large extent in line with Cunningham’s (2006) argument. Bakke, Cunningham and Seymour’s (2012) conceptualization of rebel movement fragmentation is another important contribution in this literature. Looking at the fragmentation of rebel movements, they created a conceptualization that encompasses the number of organizations, institutionalization, and

5 A rebel movement is a collective term referring to all the rebel organizations fighting the government in one conflict, while rebel organization refers to individual organizations as coded by the NSA dataset.

19 power distribution between factions in a rebel movement. Together, these three factors create a continuous measure, going from cohesion to fragmentation. Based on this conceptualization, they find that the pattern of fragmentation within a rebel movement determines the degree of infighting in the movement (ibid:278). Moreover, they argue that these patterns of fragmentation are likely to influence the dynamics and outcome of conflicts. In another article focusing on rebel movement fragmentation, Cunningham, Bakke and Seymour (2012:83) find that the number of other violent factions within a rebel movement significantly increases violence against co-ethnic civilians. Fragmentation is thus significantly related to the actions of rebel organizations.

In relation to conflict duration, Findley and Rudloff (2012:882,899) argue that fragmentation can lead to shorter wars that end in a negotiated agreement, in stark opposition to Cunningham’s (2006) theory. They explain this by claiming that fragmentation weakens the resulting rebel movement, making the conditions more conducive for cooperation. This argument is to some extent supported by Asal, Brown and Dalton (2012:96), who argue that rebel groups with a centralized leadership structure are better able to withstand counterinsurgency than organizations with factionalized leadership structures. There are consequently different views of how fragmentation affects the dynamics of civil war, depending on the focus of the researchers. Yet, all of these analyses reveal that organizational structure and fragmentation have a significant impact on the dynamics of conflict.

Quantitative analyses have thus increasingly focused on the effect of rebel movement cohesion on bargaining and conflict duration in recent years. However, there is a gap in this literature in that most analyses of bargaining and fragmentation focus on rebel movements rather than the organizational structure of individual rebel groups. This is curious, in light of the insistence by the same researchers that rebel organizations are not unitary actors, but vary in levels of central control and internal cohesion. I argue that we need to extend the lessons learned from these analyses of rebel movement fragmentation to the individual rebel groups.

Organizational theory has revealed that the central organization of rebel groups determines its control over recruits, and consequently over the factions within the organization. The argument that fragmentation affects the bargaining process should therefore also apply for individual rebel organizations, meaning that we need to look at the internal cohesion of rebel organizations to better understand their bargaining position in relation to the government.

2.3 My contribution

Based on the discussion above, it is clear that while there have been significant improvements in both the horizontal inequality literature and the organizational literature in recent years, there is still need for further research on these topics. With this thesis, I aim to add to the theoretical dialogue and contribute to the literature on conflict duration.

Firstly, most conflict analyses are state-centric, focusing solely on the characteristics of the state and the government army. However, the dynamics of a civil war are not controlled by the government, but rather by the dyadic relationship between the state army and the rebel organization. Several analyses of rebel organization have uncovered that the characteristics of the rebel group significantly affect how conflicts unfold (Cunningham, Gleditsch and Salehyan 2009). When theorizing about the duration of conflict, we should therefore focus on the traits of the rebel organization. This thesis focuses on the characteristics of rebel groups when explaining the duration of conflict. It consequently positions itself in the literature on dyadic conflict dynamics, as it reveals that the characteristics of the rebel organization play an essential part in explaining conflict duration.

Secondly, by building on the theoretical framework by Cederman, Gleditsch and Buhaug (2013), the thesis adds to an existing dialogue on excluded ethnic groups and conflict duration. However, by focusing solely on the bargaining process and giving a more detailed account of the mechanisms through which horizontal inequality prevents the peaceful settlement of conflicts, the thesis extends their theory. Moreover, this thesis gives specific attention to the mechanisms through which horizontal inequality affects rebel organization’s ability to retain recruits. This is done in order to better specify the theoretical foundation of Cederman, Gleditsch and Buhaug’s argument. As such, this thesis contributes to the literature on horizontal inequality and conflict duration. At the same time, it also brings new focus to the effect of horizontal inequality mobilization on sustaining rebel organizations.

Thirdly, articles on excluded ethnic groups and conflict duration argue that organizational cohesion helps these rebel groups retain recruits in their theoretical frameworks, while ignoring the organizational level in their quantitative analyses. There is consequently a gap between their explanations and their analyses. In this thesis, the organizational structure of rebel organizations is brought into the theoretical framework in order to allow for a more

21 comprehensive understanding of how rebel organizations sustain conflict. By introducing theory on organizational structure into the theoretical framework, I attempt to bridge the gap between horizontal inequality theory and organizational theory – a step that is theoretically relevant, as both of these theories focus on bargaining problems when explaining sustained conflict.

Fourthly, quantitative research on the effect of organizational structure on conflict duration is still in its infancy, and the few analyses that are out there focus on fragmentation of rebel movements rather than the cohesion of the independent rebel organizations. As such, there is a need to develop this literature to see if the factors that have been found to be fruitful explanatory factors in relation to bargaining with fragmented rebel movements also provide insight into bargaining with fragmented rebel organizations. By including the organizational structure of rebel groups into the analysis, this thesis builds on the argument laid out by Cunningham (2006) and other researchers on rebel movement fragmentation. However, by bringing the focus down to the rebel organization level, I seek to expand on this literature.

Finally, the thesis presents a new theoretical argument, as it proposes that the effect of horizontal inequality is interdependent on the effect of organizational structure. There is no published research – to my knowledge – that looks at the combined effect of these two factors on sustaining conflict. By introducing these two factors as my main explanatory variables of conflict duration, I aim to further our knowledge on horizontal inequality and organizational structure. The high presence of civil war in the world today is explained by sustained conflicts rather than conflict onset. It is thus of both political and theoretical interest to see whether the factors that improved our understanding of the onset of conflict also explain why conflicts endure.