Operations

Chapter II
2. Law of War Principles
The law of war regulates the conduct of states and combatants engaged in armed conflict
hostilities and is often referred to as the law of armed conflict. The law of war is inspired in
part by a humanitarian desire to diminish unnecessary suffering during armed conflict. It
provides protections for all classes of persons recognized by the law of war including
combatants, noncombatants, and civilians from unnecessary suffering, and establishes
safeguards for civilians, prisoners of war, and the wounded and sick. The law of war also
attempts to prevent degeneration of conflicts into savagery and brutality, thereby facilitating
the restoration of peaceful relations which must, at some point, follow the conclusion of
hostilities. It is DOD policy that US forces follow the law of war in all military operations.
Therefore, legal advisors help ensure that the JFC and staff consider law of war principles
during the planning process for all joint military operations, and particularly during planning
for combat operations. Some of the key law of war principles to be considered during the
planning process are as follows:
a. Military Necessity. The principle of military necessity states a belligerent is justified
in the use of all measures needed to defeat the enemy as quickly and efficiently as possible
that are not forbidden by the law of war. Military necessity justifies actions, such as
destroying and seizing persons and property. However, this principle is not applied in a
vacuum. It must be applied in conjunction with other law of war principles. For example,
the principle of distinction (discussed in paragraph 2c, “Distinction”) generally prohibits the
intentional targeting of protected persons (civilians, hostile personnel who have surrendered
or are otherwise “out of combat,” etc.) and places (objects or places that are used for purely
civilian purposes, such as hospitals, schools, and cultural property that have not been
converted to or for military/hostile use) because they do not constitute legitimate military
objectives in furtherance of the accomplishment of the mission.
b. Humanity. Although military necessity justifies certain actions necessary to defeat
the enemy as quickly and efficiently as possible, military necessity cannot justify action not
necessary to achieve this purpose, such as cruelty or wanton violence, or the use of weapons
that are calculated to cause superfluous injury. Moreover, once a military purpose has been
achieved, inflicting more suffering is unnecessary and should be avoided. For example, the
principle of humanity forbids making enemy combatants who have been placed hors de
combat the object of attack. Generally, weapons and ammunition that have been issued by
DOD have been reviewed to ensure compliance with the law of war and this principle.
However, approved weapons and ammunition also may not be used in a way that will cause
unnecessary suffering or injury.
c. Distinction. The principle of distinction, sometimes referred to as the principle of
discrimination, requires parties to a conflict to distinguish between combatants and
noncombatants and to distinguish between military objectives and protected property and
places. Parties to a conflict must direct their operations only against military objectives.
Military objectives are combatants and those objects that, by their nature, location, purpose,
or use make an effective contribution to military action and whose total or partial
destruction, capture or neutralization, in the circumstances ruling at the time, offer a
definitive military advantage.
II-2 JP 1-04