Final answer:
The portion of the law of war pertaining to unnecessary suffering applies regardless of whether combatants use lawful weapons or not.
Step-by-step explanation:
The portion of the law of war pertaining to unnecessary suffering applies regardless of whether combatants use lawful weapons or not. The law of war aims to limit the suffering and protect the dignity of individuals involved in armed conflicts. It prohibits the use of any weapons or tactics that cause unnecessary pain or suffering, regardless of their legality. For example, the use of chemical weapons, such as mustard gas, is prohibited under the law of war because it inflicts severe and unnecessary suffering.