Which theory states that combatants must distinguish between military targets and civilian populations?

The principle that mandates combatants to differentiate between military targets and civilian populations is known as the principle of distinction. This fundamental tenet of international humanitarian law (IHL) underscores the necessity to protect civilian life and property during armed conflicts. It requires that all parties involved in warfare distinguish between those who are participating in hostilities and those who are not, particularly civilians, who must not be targeted.

This principle is critical for minimizing harm to non-combatants and is designed to ensure that military operations focus solely on legitimate military objectives, thus upholding moral and legal standards during warfare. By adhering to the principle of distinction, military forces aim to engage only military objectives and reduce collateral damage to civilians and civilian infrastructure. Therefore, this principle not only serves a legal function but also contributes to the ethical conduct of warfare.