Baker A, Scarritt JR, Mozaffar S. DEMOCRATIZATION. 23 (5) (August 01, 2016): 838-861.

Ethnic fragmentation is largely presumed to be bad for democracy. However, many African countries belie this claim, as democracy has recently sprouted in several of its multiethnic states. We argue that African countries that have demographic patterns where the largest ethnopolitical group is at least a near-majority and is simultaneously divided into nested subgroups produce Africa's most democratic multiethnic societies. This large-divided-group pattern, which has gone largely unnoticed by previous scholars, facilitates transitions to democracy from authoritarian rule. The large group's size foments the broad-based multiethnic social agitation needed to pose a genuine threat to a ruling autocrat, while its internal divisions reassure minorities that they will not suffer permanent exclusion via ethnic dominance under an eventual democracy. We support our claim with cross-national quantitative evidence on ethnic fragmentation and regime type.