Like Nation or God, Public Opinion is a conceptual being or a sociosemiotic object which orients political processes and configures public debates even though it is, from a strict ontological standpoint, an intangible and deferential “entity”. To understand how public opinion has thus become the ultimate authority figure in modern democracies, we have to resort to a method that is archeological in nature. It consists of following the circulation, transformation and “ontologization” of public opinion from its emergence in the Republic of Letters to its recognition as a supreme instance of government during the French Revolution of 1789 and then to its more contemporary factualization as the output of polling methods and survey apparatus. Although the figure of public opinion is now endowed with relative sociosemiotic stability, it still encapsulates the semantic and political tensions between social multiplicity and political unity, freedom and constraint, contract and obedience, common opinion and general interest, that characterize it from its emergence. The saliency of these different tensions depends upon the order of worth and organizational configuration that define the social spaces and arenas that public opinion goes through. Nowadays, the rise of populism tends to reduce public opinion to the expression of a preexisting identity, generally ethnic or national, that the leader would incarnate “in person”, violating thereby the ventriloquial relationship of representation that characterizes democracy. However, this populist reduction may well be temporary. Indeed, the semiotic materiality of a concept such as public opinion might be robust enough to combat its degradation and reactualize the normative ideal that still remains one of its constitutive features.