United States of America
Practice Relating to Rule 1. The Principle of Distinction between Civilians and Combatants
Section A. The principle of distinction
The US Air Force Pamphlet (1976) states: “In order to insure respect and protection for the civilian population and civilian objects, the parties to the conflict must at all times distinguish between the civilian population and combatants.”
The US Naval Handbook (1995) states: “The law of armed conflicts is based largely on the distinction to be made between combatants and noncombatants.”
The US Naval Handbook (2007) states: “The principle of distinction is concerned with distinguishing combatants from civilians and military objects from civilian objects so as to minimize damage to civilians and civilian objects.”
In explaining the US Government’s position on the basic principles applicable in armed conflicts before the Third Committee of the UN General Assembly in 1968, the US representative stated that the principle of distinction, as set out in draft General Assembly Resolution 2444 (XXIII), constituted a reaffirmation of existing international law.
Subsequently, US officials have referred to General Assembly Resolution 2444 (XXIII) as an accurate statement of the customary rule that a distinction must be made at all times between persons taking part in hostilities and the civilian population.
In 1991, in response to an ICRC memorandum on the applicability of IHL in the Gulf region, the US Department of the Army pointed out that “the obligation of distinguishing combatants and military objectives from civilians and civilian objects is a shared responsibility of the attacker, defender, and the civilian population as such”.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Article 48 of the 1977 Additional Protocol I “is generally regarded as a codification of the customary practice of nations, and therefore binding on all”.
The US Department of Defense also stated:
The law of war with respect to targeting, collateral damage and collateral civilian casualties is derived from the principle of discrimination; that is, the necessity for distinguishing between combatants, who may be attacked, and noncombatants, against whom an intentional attack may not be directed, and between legitimate military targets and civilian objects.
According to the Report on US Practice: “It is the
opinio juris of the United States that … a distinction must be made between persons taking part in the hostilities and the civilian population to the effect that the civilians be spared as much as possible.”
In March 2010, in a speech given at the Annual Meeting of the American Society of International Law, the US State Department’s Legal Adviser stated:
[T]his Administration has carefully reviewed the rules governing targeting operations to ensure that these operations are conducted consistently with law of war principles, including:
- First, the principle of distinction, which requires that attacks be limited to military objectives and that civilians or civilian objects shall not be the object of the attack;
…
In U.S. operations against al-Qaeda and its associated forces – including lethal operations conducted with the use of unmanned aerial vehicles – great care is taken to adhere to these principles in both planning and execution, to ensure that only legitimate objectives are targeted.

[emphasis in original]