The origins of genocide have been sought by scholars in many areas of human experience: politics, religion, culture, economics, demography, ideology. All these of course are valid explanations, and go a long way to getting to grips with the objective conditions surrounding genocide. But, as Berel Lang put it some time ago, there remains an inexplicable gap between the idea and the act of mass murder. This article aims to be a step towards bridging that gap by adding a human (...) dimension to the existing explanations. Building on Roger Caillois’s anthropological analysis of ‘war as festival’, Georges Bataille’s concept of society’s ‘excess energy’, and Emile Durkheim’s idea of ‘collective effervescence’, and connecting these terms to those used explicitly in relation to the Holocaust by Dominick LaCapra (‘scapegoating’ and the ‘carnivalesque’) and Saul Friedl‰nder (‘Rausch’ or ‘ecstasy’), I argue that prior to and during any act of genocide there occurs a heightening of community feeling, to the point at which this ecstatic sense of belonging permits, indeed demands, a normally forbidden act of transgression in order to ‘safeguard’ the community by killing the designated ‘threatening’ group. This article is a theoretical starting point aimed at stimulating discussion, in which I refer to the Nanjing and My Lai massacres and the genocides in Nazi Germany and Rwanda to show where empirical research is needed to illustrate this concept of ‘genocide as transgression’. (shrink)