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  • Insurgent Fragmentation in the Horn of Africa: rebellion and its discontents by Michael Woldemariam
  • Corinna Jentzsch
Michael Woldemariam, Insurgent Fragmentation in the Horn of Africa: rebellion and its discontents. Cambridge: Cambridge University Press (hb £75 – 978 1 108 42325 0). 2018, vii + 330 pp.

The political histories of Ethiopia and Eritrea with their myriad rebellions have long fascinated researchers interested in armed conflict, but a systematic analysis of the evolution of the region’s rebel groups has been lacking. This book takes up this challenge, providing an excellent contribution to research on how rebellions fall apart, and a deep analysis of those movements that shape contemporary politics in both countries.

Michael Woldemariam seeks to understand why rebel groups disintegrate – an important concern, as rebel cohesion and fragmentation can affect the intensity and duration of civil wars. Making use of a quantitative analysis of rebel groups in Ethiopia, as well as detailed histories of the Eritrean Liberation Front (ELF or Jebha) and the Eritrean People’s Liberation Front (ELPF or Shaebia), and extending the argument to other armed groups in Ethiopia, Eritrea and Somalia, Woldemariam presents a carefully crafted and meticulous study. The book compares evidence from an impressive range of sources, including archival and original interview data collected during fieldwork in Ethiopia, Somalia, Kenya, Sudan, Europe and North America.

The book’s innovation is to refocus attention on the temporal dimensions of rebel splits – the changing demands of war over time and how they have an impact on rebels and their organizations. Rebel cohesion and fragmentation have been the focus of much recent research in conflict and security studies, but most arguments have looked at the impact of internal characteristics of armed groups or of their external relations. Woldemariam makes an important adjustment to Fotini Christia’s theory (see Alliance Formation in Civil Wars, 2012), which explains alliances between rebel groups in multiparty civil wars in terms of wins and losses on the battlefield. While Christia expects battlefield wins to foster cohesion within armed groups and losses to lead to fragmentation, Woldemariam argues that wins can also result in factionalism and fragmentation, as they may trigger a conflict over the distribution of the spoils of war. Cohesion, as the book demonstrates, is a result of military stalemates (‘cohesive stalemates’), during which the external threat motivates armed groups to remain together, while not being strong enough to threaten the individual factions’ survival.

The theoretical underpinning of the argument is that each rebel organization is made up of factions. Inspired by the neorealist tradition in international relations, Woldemariam maintains that factions are like units in an anarchic system that fight for their own survival. If the survival of individual factions is at stake, then a collapse of the coalition is likely. However, to fully account for the dynamic process of moving from coalition to factionalism and then to fragmentation, we would need to know more about the internal characteristics of factions and their motivation to solve factional conflicts by leaving the coalition. In the author’s explanatory framework, the two-step process of factionalism (tensions between factions) and then fragmentation (splits between factions) is collapsed into one. But why, for instance, did certain battlefield gains and losses lead to factionalism, but not to rebel splits (p. 183)?

Like the neorealist perspective that he draws on, Woldemariam tends to overemphasize conflict – and rebel splits. While the book has implications for a theory of the cohesion of armed groups, it prioritizes fragmentation both theoretically and empirically. The mechanisms that drive factions apart when rebels face military gains or losses are well evidenced. However, the process by which stalemates keep factions together remains largely unexplained. The theory points to the role of external threats, which appear to be at an equilibrium during stalemates. But do these external threats remain the same over time? Some stalemates [End Page 421] are very violent, as the case studies reflect (p. 178), but we do not know what the effect is of that violence. One could imagine that high levels of violence or a long-lasting stalemate would have an effect on the available resources, fighters’ morale, and the rebels’ vision for what is possible to achieve...