This paper discusses the construction of a formal model of national political development derived from theories of political integration and instability, and reports the results of tests of the model based on data descriptive of contemporary black African nations. Political integration is conceptually elaborated in terms of processes of horizontal, vertical, and value integration, and political centralization. Political instability is conceptualized in terms of elite, communal, and mass instability. These dimensions of integration and instability are operationalized, and the analysis evaluates the hypothesis that integration decreases the likelihood of political instability in African nations, and that political centralization, in particular, decreases the likelihood of political instability by modifying, or reinforcing, the effects of other processes of integration. Methodologically, the analysis is based on the assessment of convergent validation for hypotheses tested with multiple indicators, regression, and path-analytic techniques.