Under international law, for example the Hague, Geneva conventions and case law estabilished by various international bodies such as ICC, UNSC, UNGA, International Military Tributal (IMT)...
Are soldiers, and not just commanding officers, criminally responsible for fighting under a war of aggression (assuming that they are on the side of the aggressor)?
Can the Nuremberg defense be made? Must these soldiers refuse the orders of their commanding officers?
Is there a difference between drafted soldiers and those that sign up?
An example in recent history: Are privates in the US army responsible for the war of aggression against Iraq, if they participated in that war, and could they be prosecuted if there were such a body willing to do it (I know that the Rome statute and War of Aggressions are in a bit of a bind)?