Introduction

Pro-government militias (PGMs) are a prominent feature of civil wars. In Iraq the United States sponsored the Sunni Awakening groups to fight against insurgents. Afghanistan formed militias to battle the Taliban. Over the course of the Syrian civil war, the number of militias fighting for Bashar al-Assad has increased and includes Shia militias supported by Iran and Hizbullah from Lebanon. While religious cleavages shape the supply of irregular armed groups in the Middle East, these groups can be found in counterinsurgency (COIN) campaigns across the globe. In eastern Ukraine, pro-Ukraine militias fight against pro-Russia armed separatists, in northern Nigeria the Civilian Joint Task Force battled Boko Haram, and in Colombia rural defense groups assist the government against FARC. While gaining increasing attention in the media, using irregular forces against insurgents has a long history and was a common element of colonial security sectors (e.g., Anderson, 2005; Janowitz, 1977; Thompson, 1966). The British used Assyrian militias in Iraq to assert authority under the auspices of the League of Nations mandate for the territory (Ahram, 2011, p. 62). They used auxiliaries in Ireland, many of whom went on to serve in the Palestine in the 1920s, and they created Home Guards in Malaya and Kenya to defeat insurgencies in the 1950s (Anderson, 2005; Branch, 2009). In fact, many elements of COIN strategies “call for the use of local militias to extend armed presence or allow locals to have a stake in their own security” (Paul, Clarke, & Grill, 2010, p. 62).

Responding to rebel threats with this sort of public–private collaboration occurs across conflict types, rebel actors, and regime types. Assuming a unitary or “Weberian” state actor masks the creativity of governments in combatting insurgents. Across various research fields scholars are increasingly attentive to the activities of armed groups recruited or induced to side with the state (e.g., Blocq, 2014; Jentzsch, Kalyvas, & Schubiger, 2015; Kowalewski, 1992; Lyall, 2010; Stanton, 2015). Attention to these organizations mirrors the wider academic interest in non-state actors and in “not-entirely state” and “not entirely private” (Ostrom, 1990) solutions to policy problems. It is an analytically rich seam of questions and controversies.

We review research on the role of irregular pro-government armed groups in civil wars. After defining pro-government militias, we examine why governments use militias in counterinsurgency campaigns, despite the risks of outsourcing violence. To understand the use of these groups, both the demand and supply side require attention. Using descriptive statistics, we overlay PGM presence on various categories of civil war, building upon the literature on classifying civil wars. We focus the discussion on the effectiveness of militias in COIN campaigns and levels of violence against civilians. We conclude with some challenges for future research.

Pro-Government Militias in the Context of Armed Conflict

Some scholars enlarge the scope of militias to include non-state actors without specific links to government. In a special issue on militias, Jentzsch et al. (2015) use the term militia for an armed non-state actor that is “anti-rebel.” Militias sometimes also include rebel groups (e.g., Bates, 2008; Raleigh, 2016). Instead of focusing on the link to the government, other classifications claim that the link to political actors is analytically more useful than a link to government, as groups may fight for the opposition as well (Schuberth, 2015, p. 306). With changes of government, groups linked to political parties, for example, may no longer be pro-government. But the puzzle remains of why governments, with regular forces available, continue to rely on non-state armed groups. The relationship between the government and militias is diverse and very dynamic, ranging from incorporation to suppression (Staniland, 2015). This review of pro-government militias fits best Staniland’s typological category of “collusion.” We limit our review to armed groups that contribute to counterinsurgency campaigns and that have a link to the government beyond sharing an enemy. We exclude private armed groups of landlords or criminal gangs, unless there is a link to either subnational or national government under civil war conditions.

We define militias as armed groups linked to the government and separate from the regular forces but limit our focus to those operating within the context of counterinsurgency campaigns and civil wars (Carey, Mitchell, & Lowe, 2013, p. 250). The term “paramilitary” may include these groups, but is also often inclusive of regular professional units such as police forces and border guards (Dowdle, 2007). Similar to Jentzsch et al. (2015), we exclude private security firms due to their status as commercial contractors. To further distinguish private security firms from militias, these researchers add territorial conditions, noting that in contrast to military contractors, militias tend to operate at home rather than abroad. We relax the territorial condition and consider militias operating both within and across borders in the context of conflict. But the incentives for governments to contract with these firms (Avant, 2005) may be similar to those that motivate alignment with militias. Our definition also includes surrogate forces, which Hughes and Tripodi (2009) divide into home guards, militias, counter-gangs, and pseudo-gangs. According to their classification, pseudo-gangs are government-sponsored supposedly independent groups that target rebels or terrorists, while counter-gangs (a term for co-ethnic armed groups used in defeating Mau Mau in Kenya) are lightly armed, mobile gangs, often consisting of former rebels, fighting insurgencies. Militias are identified as larger, mobile forces aligned with the government, while they define home guards in terms of the “static defence of villages” (Hughes & Tripodi, 2009, p. 9). Similarly, Clayton and Thomson (2014) and Peic (2014) identify civil defense forces as armed groups that recruit civilians or former rebels, operate locally, and are defensive rather than offensive. This work highlights the significance of ties to the civilian population and whether these militias are local or community organizations (e.g., Daly, 2016; Jentzsch, 2014).

Why do governments create or align with irregular forces when fighting a rebel group? Why do governments not merely strengthen regular forces, which are likely to be better equipped, better trained, and more disciplined? Hughes and Tripodi (2009) point out the disadvantages of militias. They undermine the government’s authority and may not be fully under the government’s control. They are often characterized by internal strife and may lack discipline, accountability, and reliability. Their agendas or ideological preferences may differ from the government (Hughes & Tripodi, 2009). Yet despite these disadvantages, between 1981 and 2007 over 80% of country-years with armed conflict generating at least 25 battle-related deaths included pro-government militias (Carey et al., 2013, p. 255). They are not a phenomenon confined to the post–Cold War era or restricted to certain continents. In the following we review arguments offered to explain the use of pro-government militias in civil wars.

Why Use Militias to Fight Insurgents?

Types of Civil Wars and PGMs

If general incentives drive demand for these groups, and if the government subsidizes the creation of them, then militias will not be restricted to states at a particular point on the path to development or to a particular region of the world. We note that some theoretical arguments point to the importance of specific historical trajectories (Ahram, 2011), but if we accept that militias can appear anywhere, we need to explain why PGMs might be more likely to be used in some types of conflicts compared to others, since they are not present in all conflicts and not at all times.

The UCDP/PRIO Armed Conflict Dataset (Gleditsch, Strand, Eriksson, Sollenberg, & Wallensteen, 2002; Themnér & Wallensteen, 2014) distinguishes between two types of civil wars depending on the driving factor behind the conflict. Governmental conflicts are about the government, e.g., the political system or the replacement of the central government; territorial conflicts are about the insurgents’ demands for territory. Figure 1 shows the percentages of governmental conflicts per year that had at least one PGM, using information from the Pro-Government Militias Database (PGMD) (Mitchell & Carey, 2013). The graph differentiates between informal PGMs, which have only a loose link to the government, and semi-official PGMs, which are officially recognized and often formally included within the structure of the security forces, while being separate from regular military or police (Carey et al., 2013).

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Figure 1. Pro-government militias in governmental conflicts.

While the proportion of governmental conflicts with informal PGMs increased from a low of 20% in 1983 to 75% in 2003, the proportion of such conflicts with the semi-official PGMs declined. In 2006 half of all governmental conflicts had both informal and semi-official PGMs. The increase in the proportion of conflicts with informal PGMs might reflect an artifact of the data and increasing media coverage of such forces over time. Alternatively, it might reflect the increasing benefit of denying responsibility for violence since the end of the Cold War, which makes outsourcing to informal PGMs particularly attractive. With the rise of human rights on the international agenda, for example, the EU’s Copenhagen Criteria of 1993 and political conditionality for foreign aid, governments have an increasing incentive to distance themselves from repression.

Figure 2 plots the proportion of territorial conflicts with PGMs between 1981 and 2007. Again, the percentage of conflicts with informal PGMs sharply increases in the mid-1990s. But throughout the period more conflicts feature semi-official PGMs compared to informal militias, suggesting that governments are less willing to rely on irregular forces that pose the most severe delegation and control problems. Additionally, semi-official PGMs allow the government to publicly demonstrate a local or ethnic component to counterinsurgency that can be useful in tackling the secessionist struggle.

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Figure 2. Pro-government militias in territorial conflicts.

For an alternative classification, Kalyvas (2005) uses the type of warfare between government and rebels. Conventional civil wars are conflicts with resource parity between the two actors at a high level of resources. Symmetrical non-conventional (SNC) civil wars also have parity between the actors but at a low level of resources. Finally, irregular civil wars have high incumbent resources but low rebel resources. Figures 3 and 4 combine data on these different types of civil wars based on Balcells and Kalyvas (2014) with the PGMD.

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Figure 3. Different types of warfare and prevalence of PGMs

For each type of civil war—conventional, irregular, and symmetrical non-conventional —Figure 3 plots the percentage of the respective conflict type with PGMs. The unit of analysis is the conflict. The dark blue columns are the percentage of civil wars that had at least one PGM in the first year of that type of conflict, while the light blue columns represent the percentages with at least one PGM in the final year of the conflict. The data range from 1981 to 2007. Conflicts ongoing in 2007 were excluded. The figure differentiates between informal and semi-official PGMs, although the patterns are very similar. A larger percentage of conventional civil wars have PGMs at the beginning rather than the end of the conflict. This trend is slightly more pronounced for informal PGMs, and raises the question of how PGMS merge, die, or “fade away,” which has received little attention in the research literature (but see Staniland, 2015, for a discussion of the strategic choices of incorporation and suppression). Informal PGMs are most likely found when an irregular civil war comes to an end. Governments that did not have links to irregular forces at the onset of the irregular conflict did so when the conflict ended. This appears consistent with the finding that militias are usually not present at the beginning of the conflict but on average appear four years into the conflict (Peic, 2014, p. 175).

In irregular and particular SNC conflicts, the proportion of conflicts with informal PGMs is higher at the end than at the start of the conflict. The sharp increase in informal PGMs across SNC civil wars when these types of conflict end could reflect the multiplication of irregular forces in weak states. During conflicts in weak states, armed groups might “bandwagon” to benefit from being aligned with the government, for example, with weapons, payment, or immunity. If the conflict is ethnic, then Kalyvas suggests that ethnic defection increases as conflicts reach the “latter stages” (2008, p. 1051).

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Figure 4. Different types of warfare and number of PGMs

Figure 4 plots the number of PGMs found in the different types of civil war, at conflict start and conflict end. While the share of irregular conflicts with PGMs increases over the conflict cycle, the actual number of PGMs drops. What explains these patterns? Do governments actively merge or reduce the number of PGMs when fighting a guerrilla war, or do governments only get involved in or dragged into irregular warfare if they have distributed their authority to use violence across a large number of irregular forces? Future research has important questions to tackle on the life cycle of PGMs and the dynamics of civil war.

How Effective Are Militias, and What Price Do Civilians Pay?

While many conflicts feature pro-government militias, do they provide an advantage to governments and prevent an outright loss to the rebels, or can they turn a conflict into a government victory? What price do civilians have to pay when PGMs are involved? The literature provides a mixed picture of PGM violence against civilians. Analyzing the conflict in Chechnya, Lyall (2010) shows the tactical effectiveness of using co-ethnic, locally informed militias in comparison to regular Russian troops. He uses Geographic Information System mapping (GIS) and news sources to collect data on the location and number of militia and on regular force operations and insurgent attacks in the Chechen conflict and a matching technique for the regression analyses. His findings suggest that these groups contributed to regime security. It is less clear how to assess the comparative harm done to the local population by the different types of forces. While Lyall finds Russian forces killed and disappeared more individuals, the militias kidnapped greater numbers (2010, p. 14). He quotes a local non-governmental organization (NGO) representative: “The kadyrovtsy are much more dangerous for local residents in terms of persecuting entire families or kidnapping individual relatives … The federal [Russian] troops simply don’t have such complete information about the local residents” (Lyall, 2010, p. 15). Šmíd and Mareš’s (2015, p. 15) qualitative case study of the Chechen conflict also finds that Putin’s policy of “Chechenizing” the conflict was successful. Russia enlisted Chechen clans as paramilitary forces, but according to their account at the price of violent excesses.

Using micro-level data from the Philippines between 2001 and 2004, Felter (2007) compares the military effectiveness of elite forces, regular forces, and civil defense forces. He evaluates effectiveness along four dimensions: striking targets effectively with minimum collateral damage, central monitoring with decentralized execution, access to local information, and signaling credibility in victory. He shows that the civilian defense forces, the Civilian Armed Forces Geographical Units, perform worse than the other types of forces across all categories. Local knowledge appears to lead to feuds and vendettas and makes them targets for rebel violence. As a result, they suffer much higher casualties than regular or elite forces, even controlling for their smaller size and possible differences in deployment strategies.

Additionally, Felter (2007) shows that the proportion of firearms that were lost is much higher among the indigenous forces compared to regular and elite forces. This finding highlights the risks of yielding a monopoly of violence. Felter explains these failures with poor leadership and supervision. When elite forces lead the indigenous forces, they become far more effective than either the elite forces or the regular forces (Felter, 2007, p. 26). Similarly, in Algeria, using local forces to find the guerrillas and French paratroopers to kill them was effective: “within months the ALN had lost half of its soldiers killed, captured, or converted to the French cause” (Evans, 2011, p. 245). These findings suggest that the qualities that irregular forces bring to COIN can be more fully exploited when problems of delegation are reduced by leading them with highly trained and specialized forces. But the wider evidence on civilian violence is mixed.

The collaboration between the Awakening militias in Iraq and U.S. forces provides another example where highly professional forces benefit from the knowledge and the skills of local irregular forces. In their analysis of the success of the Iraq Surge, Biddle et al. (2012) argue that neither the irregular forces nor the American troop surge on its own was sufficient to reduce the violence in Iraq in 2007. They identify the intelligence on the insurgency collected from the Awakening groups, the fact that they were no longer fighting against the coalition, and the consequences this alliance had for Shiite militias as their principal contributions to the success of the surge, noting again rising levels of violence against civilians (Clayton & Thomson, 2014). Biddle et al. (2012) contrast the forces in Iraq with those in Afghanistan. They argue that the militia forces the coalition created in that theater, the Afghan local police, was unable to recruit former rebels—which prevented a similarly successful outcome. Algeria under the French, Kenya under the British, or more recently in Kashmir, Sri Lanka, and Chechnya all saw former rebels organized to fight alongside regular forces to reverse rebel gains.

With some nuance depending on the type of militia involved, a body of research suggests that these militia forces put civilians at risk. In defeating the Mau Mau insurgency in Kenya, these local forces inflicted significant harm on civilians: “The Home Guard thus represented state-sanctioned and sponsored terror intended to bring the population of Central Kenya under the control of the incumbent regime” (Branch, 2009, p. 87). The British government also recruited “counter-gangs” or “pseudo-gangs” of former insurgents to operate alongside the Home Guard and regular forces. “Security Forces had better weapons … but they had firmly fastened one of their hands behind their back with a cord of legal difficulties which was not the case with the irregular forces” (Kitson, 1960, pp. 44–46). In Mexico in the 1990s, ruling party–based militias are reported to have been responsible for 15,000 murders in the wake of the Zapatista rebellion (Mazzei, 2009, p. 25). With cross-national conflict data, Cohen and Nordås (2015) suggest that militias that recruit children are linked to higher levels of sexual violence. Stanton (2015) argues that if militias and insurgents come from the same constituency, then militias are less likely to attack civilians. Comparing different types of militias in East Timor, Barter (2013) concludes that militias that were created by the government were more likely to attack civilians, while those that developed in self-defense against powerful rebels were more likely to behave defensively.

Using irregular forces thus carries significant risks. Kowalewski (1992) contrasts the “benevolent” with the “critical” perspective of using irregular forces. While the benevolent perspective emphasizes “the exercise of popular sovereignty” (Kowalewski, 1992, p. 72) by using private citizens to fight rebel groups, the critical view highlights limited accountability of such irregular forces, as well as their pliability by a (foreign) elite minority and their questionable, and sometimes forced, recruitment of fanatics (Kowalewski, 1992, p. 72). He analyzes five daily newspapers from the two largest cities in the Philippines during the late 1980s to evaluate whether paramilitary groups in the Philippines corresponded more closely to the benevolent or the critical perspective. Across a large range of specific indicators, Kowalewski finds support for the critical view of paramilitaries (1992, pp. 79–80). Other work suggests that pro-government militias increase the likelihood of “agent-centered violations” such as extrajudicial killings, torture, and disappearances, which are violations that fall within the capacity of individual agents and from which there might be a plausible private benefit, be it revenge, extortion, or some gratification from the violence itself (Mitchell et al., 2014). Irregular armed groups are likely to be less well equipped to train recruits and inculcate codes of conduct. Furthermore, governments might be tempted to use these groups to shift blame and alleviate legal difficulties for controversial violence (Carey et al., 2015). In contrast, some recent research challenges the usefulness of a principal-agent approach for understanding the violence committed by militias, arguing that social cohesion and diffusion (Cohen & Nordås, 2015) and strategic decisions (Stanton, 2015) provide better explanations. As empirical measures improve, we expect to have a clearer picture of levels of “agent-centered” violence attributable to different types of armed group organizations and how well these fit with the implications of a principal-agent approach.

Some studies suggest that civil defense forces contribute to effectiveness. Analyzing irregular civil wars between 1944 and 2006, Peic (2014, p. 171) finds that governments that used civil defense forces (CDFs) were defeated more rarely than those that did not use CDFs. The multivariate analyses suggest that using CDFs substantially improves governments’ chances of defeating an insurgency. Analyzing 30 counterinsurgencies, Paul et al. (2010, p. 63) show that 25 used militias or “community policing.” While 19 resulted in COIN losses, the authors caution that the use of militias cannot alone account for the losses. In 15 of these 25 COIN operations, militias were at cross-purposes, and 13 of those 15 ended in COIN losses (Paul et al., 2010, p. 63). These insights point at the core problems associated with delegation. Multiple agents complicate monitoring and likely increases discretion. Discretion can be an advantage to the principal in allowing agents to respond effectively to local conditions—what Donahue and Zeckhauser term “production discretion” (2011, p. 50)—but it becomes a disadvantage when discretion permits opportunism and shirking. We expect militias are more likely than regular forces to pursue private interests within the governments’ COIN operations. This might result in the use of excessive violence, which some studies suggest is counterproductive in fighting insurgents (e.g., Daxecker, forthcoming; Lafree, Dugan, & Korte, 2009). Paul et al. caution governments to ensure that militias do not resort to “disproportionate or illegitimate uses of force” (2010, p. xxiv). The divergent literature on the impact of government militias on human rights and civilian welfare, on COIN success, or state failure suggests that investigating the consequences of these groups is an important component of the research agenda.

PGMs in the Aftermath of Conflict

Figure 3 shows that pro-government militias are present in over 60% of irregular civil wars at the point when these conflicts end. So what happens to these groups? How do they affect post-conflict stability and security? Mueller (2003) argues that particularly in weak states, armed groups often engage in criminal activities during civil wars—even more so when irregular armed groups such as mercenary forces or death squads are used. Focusing on the disarmament and demobilization of militias in Afghanistan, Giustozzi (2008) points out how difficult it is to effectively disarm and delegitimize militias. PGMs may become the private armed forces of warlords (Marten, 2006). Wehrey (2012) describes in Foreign Affairs the conundrum posed by militias in Libya. After the elections in June 2012, militias were used as hired guns while disarmament processes were underway. The failure to disarm these forces seriously affected the stability not just of that country, but of the whole region. Mueller suggests “the key to controlling the remnants of war is the establishment of competent domestic military and policing forces” (2003, p. 511). This might be particularly difficult at the end of a civil war fought by a diversified security sector.

Civil war may provide these groups with opportunities for private gain (Hughes & Tripodi, 2009), while peace limits opportunity. Furthermore, we know that some militias have an ethnic membership and the ethnic basis of conflict is a theoretically important dimension for the duration of a conflict (Wucherpfennig et al., 2012). Ethnically defined militias may polarize ethnic groups, which creates long-term mistrust that further complicates post-conflict reconciliation. As we know from the literature on rebel groups, having multiple actors likely makes it harder to achieve a peace agreement and end the fighting (Bakke et al., 2012). If they benefit from ongoing conflict, militias might act as spoilers to peace agreements. In short, there are reasons to expect that the presence of pro-government militias will make a conflict last longer, produce increased levels of violence and abuse, and make the post-conflict period more volatile. Putting civilian defense under the leadership of regular forces might provide a way of harnessing the advantages of irregular armed forces while reducing the risk associated with them. But even in circumstances where militias act in concert with highly professional regular forces, they may bring substantial harm to the civilian population, as with the Israeli army’s use of the Lebanese Phalange militia in Lebanon in 1982, or the use of these forces by the Americans in Iraq or the British in Kenya.

Open Questions

Research focusing on the actors involved in conflict, instead of simply the structural conditions, and abandoning the assumption of unified forces on either side provides us with a richer understanding of the dynamics of civil war. Initial insights into the role of irregular forces aligned with the government, piecing together evidence from a disparate case literature and some quantitative cross-national studies, opens up new questions for future research. As in other research fields, an important first step is to sort out meaningful dimensions for classifying these organizations. While militias are found in conflicts around the world, they vary in their ties to governments or particular leaders, in their visible or clandestine activities, in their recruitment and connections to other societal, political, or economic organizations, in their size, and in national or local presence. What explains these different characteristics of PGMs, and how do these characteristics influence the effectiveness and long-term consequences of these groups on stability and peace? Also, in what types of conflicts are militias likely to develop over the course of fighting, and when are PGMs likely to escalate a conflictual situation to civil war? While case studies have provided us with important insights into these topics, more research using different approaches and covering different areas across time and space is needed for a deeper understanding of the roles of PGMs in conflict.

Accepting that there is some debate about the usefulness of a principal-agent approach (see Cohen & Nordås, 2015; Stanton, 2015), we need to know more about the details of the “contract” between these groups and their respective governments. For political scientists the structure of the relationship between the state and its armed non-state actors, the presence or absence of monitoring mechanisms and sanctions, suggests the likelihood of “adventurous” policy and the willingness of a government to evade accountability. We need to know the lines of communication between groups and government. Is there a functional equivalent of the chain of command found in regular forces? When are militia members most likely to shirk? These questions are important to research on global accountability, the state’s responsibility to protect, and to compliance and accountability issues for the international community (Grant & Keohane, 2005). Thomson (1994) describes the 1856 Paris Declaration by which the major powers agreed to end their use of letters of marque authorizing pirates to fight and loot on behalf of the state. There appears to be little progress in that direction for state authorization of irregular forces that fight on land. A ruling by the International Criminal Tribunal for the former Yugoslavia (ICTY) involving Arkan’s Tigers suggests that state officials, even if they train and arm these groups, may be freed of responsibility for their criminal conduct.

A better understanding of when these groups enter and exit a conflict is highly relevant for policymakers. Given the risks entailed, the expectation is that these groups are a desperate measure (Downes, 2006) or last resort (Peic, 2014). When do governments turn to these groups? What role does loyalty, ideology, revenge, material gain, desperation, and coercion play in their recruitment and type of membership (Staniland, 2014; Weinstein, 2007)? Furthermore, the contract is likely to entail some post-conflict expectations on all sides. As parties are added to a conflict, the conflict may become more difficult to settle. The impact of these groups on conflict duration, and more specifically on the outcome of negotiations where these groups have been involved, requires investigation. Do additional actors on the government side have the same impact on the conflict as increasing actors on the rebel side? If larger numbers on the side of the rebels results from “fragmentation” (Bakke et al., 2012) and the internal division of rebel forces, “force multiplication” or adding new forces is more likely to reflect the process of increasing the number of actors on the government side. And what does the exit of these groups entail? Are they re-integrated? Does their violence shift to criminality? What is their legacy? An innovative subnational study of post-conflict violence in Guatemala suggests these groups live on long after their wartime organization (Bateson, 2013). Survey and interview evidence from Colombia suggests that the local or community-based nature of these groups contributes to their longevity (Daly, 2016). Ties to a community, which from a principal-agent perspective may make monitoring and control easier, can help us understand their behavior during and after conflicts.

Irregular forces fighting on the side of governments may evoke images of a bygone era, of Lawrence of Arabia. Our theories of the state suggest they are a thing of the past and that security is a sovereign task. But sovereign tasks are less preciously held than anticipated. On ill-defined battlegrounds around the world, these groups continue to offer services to governments. They cheapen the material and political costs of conflict. While the short-term advantages to a particular government may be apparent, researchers need to gather the data and develop our theoretical and empirical understanding of how public–private collaboration in the security area contributes to core public goods.