The opening chapter discusses non-political societal power in political constitutions. It critically draws on the theory of societal constitutions to re-contextualise constitutionalism beyond public law, statehood and national polity. However, this theoretical approach raises the question of legitimation and authority of these non-political constitutional regimes operating independently of public reasoning. A theory of constitutional imaginaries, therefore, needs to use Foucault's analytics of power of societal norms as well as Luhmann's theory of autopoietic social systems and Teubner's theory of societal constitutions to formulate a genealogy of legal normativity and constitutionalisation of systemic facts of power by social imaginaries. Combining Foucault's conceptualisation of power as societal normalisation and Taylor and Searle's background power of knowledge, the chapter revisits the classic distinctions between potentia, potestas and auctoritas as much as the distinction between gubernaculum and iurisdictio to analyse imaginaries as societal potentia within and beyond political power and legal authority. It finally turns to Teubner's theory of societal constitutions to show that constitutional imaginaries equally draw on societal unity and difference in European and global legal pluralism and inspire new knowledge regimes constituting transnational demoi and dissent.