Key points are not available for this paper at this time.
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.The National Science Foundation provided financial support (Grant SBER-9515439; Shaheen Mozaffar, Principal Investigator) for the larger project from which this article is drawn. Scarritt supervised the data collection on ethnopolitical groups and Mozaffar supervised the data collection on elections, electoral systems, and party systems. Adrian Prentice Hull of Jackson State University and Michelle Camou and Eitan Schiffman of the University of Colorado at Boulder provided invaluable assistance in the coding of ethnopolitical groups. For many helpful comments on early drafts, the authors thank the editor and three anonymous reviewers, as well as Fabian Camacho, Gary Cox, Ted Gurr, Richard Katz, David Leblang, Arend Lijphart, Tom Mayer, Susan McMillan, Kathleen O'Doherty, Dan Posner, Donald Rothchild, and members of the Globalization and Democratization colloquium at the Institute of Behavioral Science, University of Colorado at Boulder. Mozaffar thanks the Boston University African Studies Center for continued research support. The data set for the article is available at http://webhost.bridgew.edu/smozaffar/. Final responsibility for the article rests with the authors.
Mozaffar et al. (Fri,) studied this question.