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Do electoral institutions and ethnopolitical cleavages shape the structure of party systems separately or jointly? We examine the independent, additive, and interactive effects on the number of electoral and legislative parties of two institutional variables (district magnitude and proximity of presidential and legislative elections), one intervening variable (effective number of presidential candidates), and two new measures of ethnopolitical cleavages based on constructivist specification of ethnopolitical groups (fragmentation and concentration). Ethnopolitical fragmentation independently reduces the number of parties but, interactively with ethnopolitical concentration, increases it. However, the additive and interactive combinations of both measures with electoral institutions explain the largest amount of variance in the number of parties. These results emphasize the importance of ethnopolitical cleavages in mediating the effects of electoral institutions on the structure of party systems, with important implications for the stability of Africa's emerging democracies in which parties are weak and multiethnic coalitions are fluid.

Original Citation

Mozaffar S., Scarritt J.R., Galaich G. (2003). Electoral Institutions, Ethnopolitical Cleavages, and Party Systems in Africa's Emerging Democracies. American Political Science Review, 97(3), 379-390.