Institutions and Ethnic Politics in Africa - Paperbackby Daniel N. Posner (Author), Posner Daniel N. (Author), Randall Calvert (Editor) Presenting a theory to explain how politics revolves around one axis of social cleavage instead of another, Daniel Posner examines Zambia, where people identify themselves either as members of one of the country's seventy three tribes or as members of one of its four principal language groups. Drawing on a simple model of identity choice, Posner demonstrates that the