The criminalisation of the unlawful use of force in international relations is not usually linked to conscription of an army to fight such a war. However, historical precedent in the Nuremberg and Tokyo International Military Tribunals established that conscription was part of the common plan to wage a war of aggression. After a brief history of conscription and its justifications, this article examines that precedent and then analyses how it could be put to use in a prosecution of the crime of aggression under the Rome Statute of the International Criminal Court. Finally, it argues that there is a normative case for the inclusion of conscription within the scope of the crime of aggression because of the harm done to both the conscripts and the state and people of the place they invade.