Why must lawful combatants distinguish themselves from civilians during attacks?

Under international humanitarian law, the requirement for combatants to distinguish themselves from the civilian population is a fundamental principle designed to protect non-combatants and civilian property from the hazards of war.1

The primary reason for this distinction is that failing to do so places the entire civilian population at risk. When combatants operate while disguised as civilians or fail to distinguish themselves during attacks or preparatory military operations, they blur the lines between those who may be lawfully targeted and those who must be spared. This ambiguity makes it difficult for opposing forces to direct attacks solely against legitimate military objectives, thereby increasing the likelihood of civilian casualties and collateral damage.21

While guerrilla fighters have historically faced challenges in meeting traditional requirements—such as wearing fixed, distinctive signs—modern protocols, such as the first Protocol of 1977, emphasize that combatants must at least carry their arms openly during engagements and deployments to ensure they are identifiable to the adversary. Failing to adhere to these standards undermines the ethical imperative to spare innocent lives and may result in the loss of protected status as a prisoner of war.21