FIAT · The Foundations of Institutional AuThority: a multi-dimensional model of the separation of powers

‘Almost three centuries later, it is past time to rethink Montesquieu’s holy trinity’ (Ackerman, 2010).As Ackerman (and many others) have observed, political reality has long left the traditional model of the separation of powers behind. The problems posed by this gap between constitutional theory and political practice have recently acquired fresh urgency as developments in Hungary, Poland, Turkey, Russia, the UK, US, Bolivia and elsewhere place the separation of powers under strain. These include the emergence of authoritarian leaders; personalisation of political authority; recourse to non-legal plebiscites; and the capture or de-legitimisation of other constitutional bodies. This project argues that these difficulties are rooted in a deeper problem with constitutional thinking about institutional power: a constitution-as-law approach that equates the conferral of legal power with the authority to exercise it. This makes it possible for a gap to emerge between legal accounts of authority and its diverse –and potentially conflicting (Cotterrell)– sociological foundations. Where that gap exists, the practical authority of an institution (or constitution) may be vulnerable to challenge from rival and more socially-resonant claims (Scheppele (2017)). It is this gap between legal norms and social facts that the project aims to investigate – and ultimately bridge. How is authority established? How is it maintained? How might it fail? And how does the constitution (as rule? representation (Saward)? mission statement (King)?) shape, re-shape and come to be shaped by those processes? By investigating these questions across six case studies, the project will produce a multi-dimensional account of institutional authority that takes seriously the sociological influence of both law and culture.The results from these cases provide the evidential foundation for the project’s final outputs: a new model and new evaluative measures of the separation of powers.