“What Do We Really Know about Local Peacekeeping Effects?”

The article “Violence reduction or relocation? Effects of United Nations troops presence on local levels of violence” by Laura Peitz and Gregor Reisch is one of several recent articles that explore the local effects of peacekeeping deployments. We provide an overview of accumulated knowledge and conflicting findings, and identify a few remaining gaps in the literature. The finding that more peacekeepers are better at reducing violence has been replicated by several studies, although a few studies have identified conditional effects. Taken together, studies find that peacekeepers can reduce both violence between armed actors and violence against civilians. While Peitz and Reisch do not make a distinction between different perpetrators, previous work suggest that peacekeepers are better at reducing violence against civilians by non-state actors. Peitz and Reisch are thus far one of the few studies that explores the impact of the type of peacekeepers – although the findings are ambiguous. Lastly, there is a tension in the literature between Peitz and Reisch, who claim that peacekeepers diffuse violence to nearby location, and other studies that find no such relocation effect, or even the opposite. Future work should continue to explore the local effects of peacekeeping, directing attention to questions about types of peacekeepers, local conditions as enabling factors, the role of military capabilities (as opposed to capacity), and actions taken on the ground.


Introduction
The article "Violence reduction or relocation? Effects of United Nations troops presence on local levels of violence" by Laura Peitz and Gregor Reisch explores local effects of peacekeeping by empirically examining the effects of United Nations' peacekeeping in different areas of eastern Democratic Republic of Congo (DRC). The main findings are that peacekeeping reduces violence in areas of deployments but at the same time it also diffuses violence to nearby locations. The article is a welcomed contribution to a rapidly growing section of the peacekeeping literature focusing on the local effects of peacekeeping. Inspired by Peitz and Reisch, we have identified a set of articles published in recent years that use quantitative data on the location of peacekeepers to explore the effects on violence in their area of deployment. 1 We would now like to take the opportunity to take stock of the recent accumulation of knowledge about the local impact of peacekeeping deployments, including summarizing similarities and contradictions in findings, and to identify gaps moving forward.
What is the benefit of local-level analysis of peacekeeping? Over the last two decades we have seen a large number of quantitative studies exploring the effectiveness of peacekeeping operations (for a good overview, see Di Salvatore and Ruggeri 2017). Most of this work focuses on the mission-level effects of peacekeeping, asking whether the presence of peacekeeping missions, or particular features of these missions, contribute to lower levels of violence and increased prospects for peace. However, as discussed by Peitz and Reisch, studying peacekeeping on the macro level has its drawbacks and limitations. The local perspective can add nuance to questions like when and to where peacekeepers are deployed and under what conditions peacekeeping is effective, as the disaggregated approach allows for local variation. Size and type of peacekeeping deployment, intensity of violence, type of violence, terrain, and level of ethnic polarization are all examples of factors that can vary within states. When studying peacekeeping at the local level we can better take in to account these local factors that are known to affect conflict dynamics and peacekeeping performance. Hence, we get closer to the mechanisms by which we think peacekeeping works.

What do we know by now?
One of the main findings in the study by Peitz and Reisch is that peacekeepers reduce violence in their area of deployment. Their study focuses on the local variation in eastern DRC with regards to the presence (as well as the number and type) of peacekeepers and the occurrence of political violence in the form of fighting and violence against civilians as coded by the EDACS (Chojnacki et al. 2012). Although this finding contradicts the work by Costalli (2014), who concludes that UN troops failed to effectively reduce violence during the Bosnian war, it is largely in line with other recent studies of the local effects of peacekeeping (Cil et al. 2019;Di Salvatore 2018;Fjelde et al. 2019;Phayal 2019;Phayal and Prins 2019;Ruggeri et al. 2017). While these have variying ideas about when and how peacekeeping works at the local level, most recent studies have identified a violence-reducing effect of UN peacekeeping.

Size of deployments
Peitz and Reisch find that the size of the peacekeeping deployments matters for reducing violence in the DRC, which is in line with studies of other conflicts, including cross-country sub-national comparisons. One of the first studies of the subnational impact of UN peacekeeping examines eight countries in sub-Saharan Africa, 1989Africa, -2006, finding that larger peacekeeping deployments reduce the duration of conflict in the area of deployment, but peacekeepers' ability to prevent the onset of conflicts is less clear . The same importance of the number of troops was identified in a study of all missions with a civilian protection mandate in Sub-Saharan Africa, 2000-2011 . Similarly, Phayal and Prins (2019) study UN peacekeepers' ability to reduce one-sided violence on the local level in the post-war environment of four different Sub-Saharan African conflict areas, and find that larger deployments generally reduce civilian killings. However, in both these studies the effect varies between actors (something we will return to). Other quantitative single-case analyses have also corroborated this effect. Phayal (2019) finds that in Darfur, the number of peacekeeping companies deployed to an area reduces warring parties' intentional targeting of civilians.
Despite these consistent findings, peacekeepers are unlikely to have a uniform effect everywhere they are deployed. A few studies acknowledge that the effect of increasing troop size varies with local conditions. Cil et al. (2019) in fact find no general effect of the number of troops on the number of battle-related fatalities; however, troops do reduce violence in areas with high road density, which facilitates accessibility to violence-prone areas. Di Salvatore (2018) instead explores the importance of ethnic geography, finding that in Sierra Leone UN peacekeeping is more effective in preventing one-sided violence in areas where ethnic polarization is high. The reason is that locations with low polarization means that the contestation between the parties is higher, with the consequence of more violence directed against civilians, and the challenge for peacekeepers is greater. These findings highlight the importance of learning more about how local conditions affect peacekeeping performance.

Types of violence
Peitz and Reisch examine the impact of peacekeeping on two types of violence: fighting and violence against civilians. They find that peacekeeping reduces both fighting and one-sided violence in their areas of deployment, although with some relevant variation depending on the type of deployment (we return to the issue of type of peacekeepers below). Most other studies focus on either of these types of violence, but the findings are relatively consistent. Four recent studies show that peacekeepers can reduce the level of one-sided violence in the area of deployment (Di Salvatore 2018; Fjelde et al. 2019;Phayal 2019;Phayal and Prins 2019), while two others have identified the potential for peacekeepers to reduce fighting between conflict parties Cil et al. 2019).
When it comes to one-sided violence, there is still some unresolved tension in the literature as to whether peacekeepers are equally effective in reducing violence by governments and non-state actors. Although worth mentioning, this is something that Peitz and Reisch do not address in their article. In the case of Darfur, peacekeepers seem to have effectively reduced one-sided violence perpetrated by both government and rebel actors (Phayal 2019). Interestingly, in studies covering larger sets of cases, there seems to be strong indication that UN peacekeeping is more effective in reducing rebel-perpetrated civilian targeting Phayal and Prins 2019). One potential explanation is that UN missions are dependent on the host government for consent, and thereby direct their attention to violations by non-state actors ). According to Phayal and Prins (2019), the presence of UN peacekeepers can lower the use of one-sided violence by both government and rebel actors in local areas where armed clashes between warring parties are taking place. However, in the absence of armed clashes, UN troops are only effectively reducing rebel-perpetrated one-sided violence.

Types of peacekeepers
One major advantage of the study by Peitz and Reisch is that they do not only examine the size of deployments, but also explore the impact of various types of peacekeepers. They argue that UN peacekeepers with higher levels of force projection capabilities should be more effective in reducing violence. This hypothesis stems from the theoretical reasoning that military capabilities increase peacekeepers' ability to deter, use force, and credibly address commitment problems. Studying the effect of troop capability on peacekeepers ability to reduce battle related violence, Peitz and Reisch find that aviated troops have the largest significant violence reducing effect. The effects of infantry troops and mechanized infantry are also negative but substantially smaller, while unarmed military observers are found to have a positive effect on both fighting events and fatalities. These findings are in line with the proposed hypothesis. However, the picture is less clear when looking at the effects of force projection probabilities on the reduction of one-sided violence events and fatalities (Peitz and Reisch 2019, p. 15-16). While aviated troops are found to effectively reduce one-sided violence, there is no significant effect of infantry and only vague empirical support for mechanized troops' ability to reduce one-sided violence. Meanwhile, unarmed military observers are seen to have a negative effect on the number of violent one-sided violence events, but no effect on the number of one-sided fatalities.
These findings can be compared to Phayal (2019), who finds that while the deployment size has a negative effect on civilian fatalities, the military spending of the troop contributing country does not seem to have an effect on violence reduction. According to the author, this indicates that peacekeepers do not necessarily need higher military capacity, or force, to reduce one-sided violence, this can also be done through monitoring, verification and reporting. This highlights a limitation in looking at the number or type of troops as a measure for capacity or capabilities: it does not capture what peacekeepers actually do on the ground. More research is needed to examine to what extent peacekeepers primarily deter actors from using violence, though patrols and show of force, or if they actively engage with armed actors to alter their violent behavior. While it is possible to find anecdotal evidence in favor of both those interpretations, future research should strive to gather systematic local-level data on what peacekeepers do in order to advance the empirical analysis of peacekeeping mechanisms on the ground.

Relocation effect
The last finding from the Peitz and Reich study that we want to highlight is the relocation effect.
Peitz and Reich find that peacekeepers' presence in one location can diffuse violence to other nearby areas. They propose that when the military asymmetry between the peacekeepers and the armed actors is high, weaker actors should be more prone to relocate to avoid defeat and to maintain informal advantages. The authors therefore expect peacekeeping units with higher force projection capabilities to have a larger impact on relocation. Their empirical examination lends support to the theoretical reasoning as aviated troops, which are argued to have high force projection capabilities, have a significant positive effect on diffusion of both violent events and fatalities to nearby areas. Deployment of aviated troops diffuses both onesided violence and fighting, while the presence of infantry seem to have a positive effect on the number of events in nearby areas but not on the number of deaths. The effect of unarmed military observers, however, is less clear. Unarmed peacekeepers are found to reduce violence against civilians in nearby locations, but the reasons for this remain theoretically underdeveloped.
What is potentially even more puzzling is that the identified relocation effect contradicts the findings of some other works. Fjelde et al. (2019) address the concern that peacekeepers diffuse violence to nearby locations in three different ways. First, similar to Peitz and Reich, they examine the impact of the number of troops in neighboring areas (i.e. a spatial lag of peacekeepers) on the risk of violence. Second, they explore this effect but limited to only those locations where no peacekeepers are already present. Third, they examine whether the number of troops in one location increases the risk of violence in any of the neighboring areas (i.e. the impact of peacekeepers on the spatial lag of violence) in the subsequent months. None of these tests indicate the presence of a diffusion effect. If anything, peacekeepers seem to reduce violence also in nearby locations. Similarly, Di Salvatore (2018) also finds that the presence of peacekeepers in neighboring chiefdoms is associated with lower levels of one-sided violence. This tension between Peitz and Reich and other studies warrant further attention to this question and the employment of various empirical strategies to explore this issue.

Remaining gaps
The study by Peitz and Reisch, together with the other studies of the local effects of peacekeeping, makes an important contribution to our understanding of how peacekeeping works. However, there are still several gaps that future studies should seek to address. For example, while Peitz and Reisch have taken a few steps towards disaggregating the military components of peacekeeping missions, more work is needed to explore the impact of non-military personnel categories, including the civilian component, and how they interact. Moreover, while there is fairly strong agreement about the positive impact of peacekeeping, and in particular the relevance of large deployments, there is much more to explore in terms identifying local factors that make peacekeepers more or less likely to succeed. In addition, more research is needed to clarify the importance of capabilities in relation to the number of troops. Here, existing work suggest different conclusions, which may be a result of how capabilities are operationalized. Lastly, while capacity and capabilities may be important-they are only enabling factors. What peacekeepers actually do on the ground is another thing. This is an avenue where quantitative work could make substantial progress if coherent measures of peacekeeping tasks and actions at the local level could be obtained.