The major merit of liberal politics is the formulation that the abidance to any system of rule shall have some rationale rendering any possible coercion a consented one. For this reason, the process of public justification is the most salient, and discussed upon indeed, activity of our political self-determination as citizens of democratic countries and has, accordingly, to follow an ethic of citizenship. The standard approach of political liberalism prescribes to abide to the concept of reasonableness according to which religious arguments shall be taken off the public justification. However, recent processes of liberalization or, at best, democratization in Muslim-majority countries of the MENA region show that the exclusion of religion from the public sphere is not feasible, nor potentially apt to trigger abidance to a system of law so formed. The present paper exposes the methodological and logical flaws contained in the standard moral political theory, but also those implied in a retreat from ethics as well. In light of this, the final section of the paper will invite to consider the merits of the ideal of conscientious engagement.