Nearly all multi-ethnic political systems contain more than one dimension of ethnic cleavage. Israel is divided by religion, but its citizens are also divided by their places of origin and their degrees of secularism. South Africa is divided by race, but also by language differences and by tribe. India is divided by language (which serves as the basis for its federalism), but also by religion and caste. Switzerland is divided by religion and by language. Nigeria is divided by religion, region, and tribe. Even sub-national units are frequently ethnically multi-dimensional: cities like New York, Los Angeles, and Miami all contain prominent racial cleavages, but also cleavages based on their residents' countries of origin, languages of communication, and lengths of residence in the United States.

Given these multiple bases of ethnic division, when does politics revolve around one of them rather than another? Journalists and scholars who write about the politics of ethnically divided societies tend to take the axis of ethnic cleavage that serves as the basis for political competition and conflict as a given. They write eloquently about hostilities between Hindus and Muslims in India but never pause to ask why that country's conflict takes place along religious lines rather than among Hindi-speakers, Bengali-speakers, and Marathi-speakers. They discuss the competition among Hausas, Yorubas, and Igbos in Nigeria but never stop to question why the political rivalries in that nation rage among these broad ethno-regional communities rather than between Christians and Muslims.