The law of armed conflict (LOAC) and international humanitarian law (IHL) embrace different domains. LOAC focuses on the rights of combatants while IHL, a later phase in the development of the conventions governing the practice of war, addresses the rights of civilian noncombatants and soldiers who have fallen captive or wounded. To apply either set of law and custom cogently, it is first necessary to assign civilians and soldiers to one domain or another. As the previous chapter explains, this is no mean task. Uniformed combatants and uniformed guerrilla fighters fall squarely under the purview of LOAC while innocent and uninvolved civilians enjoy the protection of IHL. Civilian combatants, the other hand, straddle both categories. As they take an increasingly active role in war, they cannot claim complete immunity from their enemy's attempt to disable them. On the other hand, they are not always vulnerable to the same ravages of war that befall full-fledged combatants.

Full-fledged combatants, those fighting in uniform or, at the very least, continuously under arms, enjoy little quarter in battle. Nevertheless, the traditional conventions of war offer them some modicum of protection in prohibiting unnecessary and ghastly harm, torture, and execution. As a practical matter, these conventions led belligerents to exclude particular weapons from the battlefield, prohibit chemical and biological warfare, condemn torture, and avoid assassination. These measures were modest. To warrant prohibition, a weapon or practice must be both fearsome and of questionable military value.