Calculation of Self-Interest and Constitutional Consensus: The Role of Ideology

Constitutional political economy's veil of uncertainty prevents citizens from identifying their specific interests under political rules and facilitates agreement on rules by moving all individuals to an average position. But the calculation of self-interest in such settings is not straight-forward; citizens require a model of how the economy works to predict the effect of rules on welfare. Political ideologies typically supply such models. Citizens subscribing to different ideological models anticipate differential treatment under a given constitutional rule, breaking down the ability of the veil of uncertainty to achieve consensus. Constitutional consensus is unlikely in the absence of ideological consensus.