This study addresses the contemporary conflict of national identity in Sudan between the adherents of Islamic nationalism and those of customary secularism. The former urge the adoption of a national constitution that derives its civil and criminal laws from the Sharia, and want Arabic as the language of instruction in national institutions. The latter demand the adoption of secular laws, derived from the set of customary laws, and equal opportunities for all African languages beside Arabic and English. In the past, the adherents of Islamic nationalism imposed the Islamic-Arab model. In reaction, secularists resorted to violence; the Islamists declared Jihad against the secularists and adopted a racial war, which has caused a humanitarian disaster. The main primary material of this research is based on a survey conducted among 500 students of five universities in Sudan. Besides, the study considers the diverse theoretical models for the formation of a nation-state, where diversity is not discouraged, but states apply laws to promote religious and ethnic diversities within one territorial state.