We present a theory of the choice of alternative democratic constitutions, a majoritarian or a consensual one, in an unequal society. A majoritarian democracy redistributes resources from the collectivity toward relatively few people, and has a relatively small government and low level of taxation. A consensual democracy redistributes resources toward a broader spectrum of social groups but also has a larger government and a higher level of taxation. A consensual system turns out to be preferred by the society when ex ante income inequality is relatively low, while a majoritarian system is chosen when income inequality is relatively high. Moreover, we obtain that consensual democracies should be expected to be ruled more often by center-left coalitions while the right should have an advantage in majoritarian constitutions. Finally, our model also provides a new rationale, based on the endogeneity of the political system, of the positive or absent (rather than negative) association between equality and redistribution transpiring from the cross-sectional evidence of developed countries presented in some recent studies. Some historical and empirical evidence supporting our results is provided.