 These principles divide the possible victims of war into two classes: combatants and noncombatants. They place no constraints on killing  combatants.[17]  But—outside of “supreme emergencies”, rare circumstances in which intentionally killing noncombatants is necessary to avert an unconscionable threat—noncombatants may be killed only unintendedly and, even then, only if the harm they suffer is necessary and proportionate to the intended goals of the  attack.[18]  Obviously, then, much hangs on what makes one a combatant. This entry adopts a conservative definition. Combatants are (most) members of the organized armed forces of a group that is at war, as well as others who directly participate in hostilities or have a continuous combat function (for discussion, see Haque 2017). Noncombatants are not combatants. There are, of course, many hard cases, especially in asymmetric wars, but they are not considered here. “Soldier” is  used interchangeably with “combatant” and “civilian” interchangeably with “noncombatant”.