INTRODUCTION

Since the publication of Gustave Le Bon's study on crowd psychology (1895) there has been a growing acknowledgement of the idea that mass or collective violence is essentially different from individual violence (Grimshaw 1970; Summers & Markusen 1999; Barkan & Snowden 2001; Tilly 2003). Horrific incidents, like those occurred during the decade of 1990 in the former Yugoslavia and Rwanda, renewed academia's interest in the most extreme forms of organized and systematic manifestations of collective violence (Ceretti 2009; Smeulers 2010). This brute reality fuelled the development of a new paradigm in criminal sciences, encapsulated in the unprecedented development of the branch of international criminal law (Bassiouni 2003; Cassese 2003; Werle 2009) and the criminology of international crimes (Smeulers & Haveman 2008). Genocide, crimes against humanity, war crimes and aggression, termed nowadays as core international crimes, offer the common ground of these two disciplines.

Although both disciplines converge on the centrality of the collective dimension of core international crimes, they diverge crucially in the way they address it: international criminal law seeks to develop concepts, categories and theories of liability apposite to determine individual criminal responsibility in the context of collective violence with systemic traits, whereas criminology urges for an ethically and legally appropriate allocation of responsibility to different kinds of actors (individual, state and state-like) with respect to different kinds of off ending conducts. In other words, whereas international criminal law analyses core international crimes mainly as instances of individual deviance, criminology analyses them as instances of organizational deviance (Chouliaras 2010c).

Another central issue is the consideration of state involvement in the commission of core international crimes. International criminal law scholars have characterized them as characteristic instances of “abuse of state power” (Bergsmo & Trifft erer 2008, 8), given that they “presume a context of systemic or large-scale use of force (…) typically a state” (Werle 2009, 32). In the same vein Schabas posits that “these are generally crimes of State, in that they involve the participation or the acquiescence of a government, with the consequence that the justice system of the country concerned is unlikely to address the issue” (2010, 40).