This essay gives an analysis of the Dutch participation in the war in Iraq and of the crucial meaning of the Rules Of Engagement when soldiers are in operation after the end of the combat but still occupying the country and participating to Law and Order activities. The authors show through the case of Eric O., the difficulty to trace the boundaries between actions of war and actions of internal security. On the one hand, the government is keen to give the military soldiers extensive powers, even if the situation is "calm". On the other hand, the prosecutor considered the shooting incident in the province of Al-Muthanna in Iraq on December 27, 2003, where an unarmed Iraqi man was fatally wounded, as a criminal case. The Eric O. case highlights the tensions in Southern Iraq, but the situation there can be compared with other parts of Iraq, with Kosovo, Afghanistan, or Sierra Leone. It opens very important questions about war, crime, security and democracy, and about the role of the soldiers.