The crime of aggression requires that the perpetrator be in a position effectively to exercise control over—or to direct—the political or military action of a state. This requirement, called the “leadership clause,” has led to the view that private individuals are excluded from criminal responsibility because they lack the necessary authority over the state policy. In this Essay, I argue against this dominant view and outline an analytical framework for criminal complicity in a war of aggression.

To adjudicate a claim on individual criminal responsibility, the court has to establish objective and subjective links between the individual and the crime. This article studies the material (actus reus/objective) elements of the crime of aggression (conduct, consequence and circumstance) and suggests a reading that solves most of the conceptual and practical issues regarding criminal responsibility for this crime. The main contribution is an ontological distinction between the material act of use of violence and the act of aggression, which are both subsumed under the term ‘state/collective act’. The former is a consequence element and therefore is to be understood in its naturalistic meaning – a perceivable result of one’s action. The latter is a legal-evaluative notion and as such constitutes a circumstance that renders the violation of the prohibitory norm (the union of conduct and consequence) as being wrongful. This distinction is crucial for the system of attribution of criminal responsibility, as different mental (subjective) elements apply to consequences and circumstances.