Relatives embrace after meeting at Asmara International Airport, after one arrived Wednesday aboard the Ethiopian Airlines ET314 flight in Asmara, Eritrea. (Tiksa Negeri/Reuters).

The first commercial flight from Ethiopia to Eritrea in 20 years took place earlier this week, signifying a historic shift in relations between the two countries, previously stalled in a rivalrous state of “no war, no peace.

The flight followed a meeting earlier this month between Ethiopian Prime Minister Abiy Ahmed and Eritrean President Isaias Afwerki. The demonstrably warm encounter — including televised embraces and shared laughter between the two leaders — led to normalized ties between the two countries, including the reintroduction of commercial flight and direct phone calls between citizens of Ethiopia and Eritrea.

Other important moves have followed, including Eritrea’s withdrawal of troops from the militarized border with Ethiopia. The two nations in the Horn of Africa have disputed the border demarcation for decades, the site of a border war from 1998-2000, during which almost 100,000 people died. A former Ethiopian province, Eritrea struggled for 30 years to seek independence from Ethiopia; the international community finally recognized Eritrea as an independent country in 1993, following a near-unanimous popular referendum for Eritrean independence.

This month’s historic developments in Ethiopia and Eritrea offer a moment to learn more about the forces that shaped the two contemporary states. In this week’s installment of the African Politics Summer Reading Spectacular, we share insights from a new book by Boston University political scientist Michael Woldemariam: “Insurgent Fragmentation in the Horn of Africa: Rebellion and Its Discontents.”


Political parties leading Ethiopia and Eritrea were previously rebel organizations. Ethiopia’s ruling coalition, the Ethiopian People’s Revolutionary Democratic Front (EPRDF), originally formed as a rebel group fighting the Derg, Ethiopia’s military regime ousted by the EPRDF in 1991. Eritrea’s ruling party, the People’s Front for Democracy and Justice, formed out of a rebel organization, the Eritrean People’s Liberation Front, which fought for Eritrea’s independence.

Woldemariam’s book draws from the Ethiopian and Eritrean cases (as well as the Somalia case) to study why rebellions come apart, or “fragment.” He defines his core concept, rebel fragmentation, as “the splitting of rebel organizations into politically distinct, mutually exclusive entities, where these entities create a new rebel organization, join an existing organization, or join forces with the incumbent government.”

Why does it matter if rebel organizations come apart? Most obviously, rebel fragmentation is important to the survival of rebellions and subsequently, their eventual success or failure. Woldemariam reviews the broad literature on rebel fragmentation to identify other, perhaps less obvious, reasons: rebel fragmentation can influence the intensity of civil war violence, impact of violence against civilians, the duration of civil wars, state failure and postwar behavior of insurgent groups, e.g., when they have transitioned into political parties.

To study rebel fragmentation, Woldemariam compiled an original data set on 171 African rebel organizations that operated between 1946 and 2006. In his analysis of publicly available sources, Woldemariam finds a third of these rebel organizations fragmented at least once, with some fragmenting multiple times.

Woldemariam conducted years of research in Ethiopia, Somalia, Kenya, Sudan, Europe and North America. His deep case studies of Ethiopian and Eritrean rebel organizations draw on more than 85 interviews with ex-combatants, ex-government officials and civilians who lived through the conflict, as well as thousands of pages of archival material. One chapter in the book studies the Somali civil war, drawing on more than 40 interviews with government officials, rebel organization veterans and NGO employees who engaged with rebel organizations.

Woldemariam’s aim in “Insurgent Fragmentation” is to understand why rebel organizations come apart. He argues that territorial gains or losses lead rebel organizations to fragment. Gaining territory can erode cooperation and lead to factional infighting in rebel organizations while losing territory can undermine the credibility of the rebel organization’s ability to achieve its goals. Stalemates, on the other hand, lead to greater cohesion and unity in rebel organizations.

Using the example of the Eritrean Liberation Front (referred to by Eritreans as “Jebha”), Woldemariam shows territorial losses in 1967 led to commitment problems and ideological struggles within Jebha whereas rapid territorial gains in 1975 triggered infighting within Jebha’s leadership. By contrast, Woldemariam finds no factionalism or fragmentation between 1971 and 1973, when Jebha experienced a territorial stalemate.

While “Insurgent Fragmentation in the Horn of Africa” may not speak much to the recent thaw in relations between Eritrea and Ethiopia, Woldemariam’s expertise in the region is deep and compelling. A solid study of rebel organizations, “Insurgent Fragmentation” offers accessible histories of rebel organizations in Eritrea, Ethiopia and Somalia (as well as a history of the formation of the Eritrean state, in Chapter 3).

Beyond the book, a prescient research article by Woldemariam published earlier this year suggested the recent selection of Ethiopia’s Abiy created an opportunity for improved Ethiopia-Eritrea relations. Anyone interested in learning more about either country, their relations to each other or about rebel organizations more broadly, should follow his work.