This paper attempts tore-examine the evolution of constitutional governments in Nigeria from 1922 to 1999 and identify their impact on National coherence. It examined the patterns and degree of the people’s involvement in these processes of constitution making and development. With emphasis on how coherent these constitution have unified the country. It adapted the historical and content analysis methods for eliciting and analyzing its data. Three research questions were drawn for the study. Among other things, the paper reveals that although, we must remind ourselves that Nigerian federalism was established to secure the country’s unity and progress in the face of strong centrifugal forces. Hence, we can say that the various constitutions have tried to ensure coherence in the country. But most importantly in ensuring sustainable conference, the constitution for the people’ republic must entrench liberty and equity of all within a federal democratic structure in which power responsibility and resources are decentralized.