This article introduces the concept of the weaponisation of emotion to analyse how emotional responses are strategically cultivated during instances of international political captivity. Using the case of Swedish EU diplomat Johan Floderus’s 2022 detention in Iran, it explores how states manipulate collective emotions – such as fear, outrage, and pride – to pursue political, ideological, or diplomatic objectives. Drawing on intergroup emotions theory (IET), it is argued that emotions are not mere by-products of crisis but deliberate tools of emotional statecraft, shaping public reactions, pressuring foreign governments, and reinforcing domestic legitimacy. Political captivity thus becomes more than coercion or negotiation. It transforms into a symbolic arena where emotional narratives escalate tensions, mobilise identity politics, and generate international support or condemnation. By linking emotion research with security and IR scholarship, this study offers a novel framework for understanding the socio-psychological dimensions of state power and highlights the volatility and strategic potential of collective emotions in global politics.