International organisations (IOs) are said to command growing levels of authority. But in studying this phenomenon, scholars predominantly focus on the formal capacities member states assign to IOs. Much less attention is paid to the effects of IO authority, that is, how authority is exerted in practice and what it does within the affected societies. Based on a case study of the African Union’s (AU) anti-coup regime, I make the case for a ‘bottom-up’ approach to IO authority, focusing on its localised enactment and effects. Analysing the AU’s authority through a governmentality lens and drawing on several months of field research, I show that the AU’s authority to govern coups is indeed effective: in commanding the re-establishment of constitutional order, the AU prescribes a particular imaginary of political order to resolve conflict and shapes the conduct of political actors in affected states by inscribing them into this order. But rather than operating in a top-down, direct way, the AU’s authority is enacted in a distant, diffuse manner. Although based on formal powers assigned to the AU, neither the way this authority is exercised nor its effects can be inferred merely from these formal powers.