Law of Armed Conflict (LOAC)

The Rules of War

Military helicopter landing in desert as group of soldiers watching
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After World War II, the Geneva Convention created a treaty among nation states to abide by in the event of future conflicts. There have been numberous conflicts since 1949 with many crimes of war being prosecuted. The rules that are to be followed are called the Law of Armed Conflict, or Law of War, and covers everything from treating prisoners of war to rules of engagement of military forces. But the most important principles of the Law of Armed Conflict you should know are the following:

1) Fight only Enemy Combatants;

2) Do not Harm Enemies who Surrender; Disarm Them and Turn Them Over to Your Superiors;

3) Do Not Kill or Torture Prisoners;

4) Collect and Care for the Wounded, whether Friend or Foe;

5) Do Not Attack Medical Personnel, Facilities, or Equipment;

6) Destroy No More than the Mission Requires;

7) Treat All Civilians Humanely;

8) Do Not Steal; Respect Private Property and Possessions; and

9) Do Your Best to Prevent Violations of the Law of War; Report All Violations to Your Superiors.

Law of Armed Conflict (LOAC) Defined

The LOAC arises from a desire among civilized nations to prevent unnecessary suffering and destruction while not impeding the effective waging of war. A part of public international law, LOAC regulates the conduct of armed hostilities. It also aims to protect civilians, prisoners of war, the wounded, sick, and shipwrecked. LOAC applies to international armed conflicts and in the conduct of military operations and related activities in armed conflict, however such conflicts are characterized.

LOAC and Law of War (LOW) Policies

DoDD 5100.77, DoD Law of War Program, requires each military department to design a program that ensures LOAC observance, prevents LOAC violations, ensures prompt reporting of alleged LOAC violations, appropriately trains all forces in LOAC, and completes a legal review of new weapons. Although some of the services often refer to LOAC as the Law of War (LOW), within this article LOAC and LOW are the same. LOAC training is a treaty obligation of the United States under provisions of the 1949 Geneva Conventions. The training should be of a general nature; however, certain groups such as aircrews, special forces, special operations, infantry, medical personnel, and security forces, etc., receive additional, specialized training that addresses the unique issues they may encounter. 

International and Domestic Law

LOAC comes from both customary international law and treaties. Customary international law, based on practice that nations have come to accept as legally required, establishes the traditional rules that govern the conduct of military operations in armed conflict. Article VI of the US Constitution states that treaty obligations of the United States are the “supreme law of the land,” and the US Supreme Court has held that international law, to include custom, are part of US law. This means that treaties and agreements the United States enters into enjoy equal status as laws passed by Congress and signed by the President. Therefore, all persons subject to US law must observe the United States’ LOAC obligations. In particular, military personnel must consider LOAC to plan and execute operations and must obey LOAC in combat. Those who violate LOAC may be held criminally liable for war crimes and court-martialed under the Uniform Code of Military Justice (UCMJ).

Military Necessity, Distinction, and Proportionality

Military necessity requires combat forces to engage in only those acts necessary to accomplish a legitimate military objective. Attacks shall be limited strictly to military objectives. In applying military necessity to targeting, the rule generally means the United States Military may target those facilities, equipment, and forces which, if destroyed, would lead as quickly as possible to the enemy’s partial or complete submission.

As an example of compliance with the principle of military necessity during Operation Desert Storm, consider our targeting and destruction of Iraqi SCUD missile batteries and of Iraqi army and air forces. These actions quickly achieved air superiority and hastened the Iraqi military’s defeat.

Weapons Review, requires a legal review of all weapons and weapons systems intended to meet a military requirement. These reviews ensure the United States complies with its international obligations, especially those relating to the LOAC, and it helps military planners ensure military personnel do not use weapons or weapons systems that violate international law. Illegal arms for combat include poison weapons and expanding hollow point bullets in armed conflict.

Distinction means discriminating between lawful combatant targets and noncombatant targets such as civilians, civilian property, POWs, and wounded personnel who are out of combat. The central idea of distinction is to only engage valid military targets. Therefore, it would be inappropriate to locate a hospital or POW camp next to an ammunition factory.

Proportionality prohibits the use of any kind or degree of force that exceeds that needed to accomplish the military objective. Proportionality compares the military advantage gained to the harm inflicted while gaining this advantage. Under this balancing test, excessive incidental losses are prohibited. Proportionality seeks to prevent an attack in situations where civilian casualties would clearly outweigh military gains. This principle encourages combat forces to minimize collateral damage—the incidental, unintended destruction that occurs as a result of a lawful attack against a legitimate military target.

ROE (Rules of Engagement)

Competent commanders, typically geographic combatant commanders, after JCS review and approval, issue ROE. ROE describe the circumstances and limitations under which forces will begin or continue to engage in combat. Normally, execution orders (EXORD), operations plans (OPLAN), and operations orders (OPORD) contain ROE. ROE ensure use of force in an operation occurs in accordance with national policy goals, mission requirements, and the rule of law. In general, ROE present a more detailed application of LOAC principles tailored to the political and military nature of a mission. ROE set forth the parameters of an airman’s right to self-defense. All airmen have a duty and a legal obligation to understand, remember, and apply mission ROE. During military operations, LOAC and specifically tailored ROE provide guidance on the use of force. The standing rules of engagement (SROE) of the CJCS give commanders direction on the use of force in self-defense against a hostile act or hostile intent. The SROE do not limit an airman’s inherent right to use all means necessary and appropriate for personal or unit self-defense. Some basic considerations based on the SROE follow:

  • The use of force in self-defense must be necessary and limited to the amount needed to eliminate the threat and control the situation.
  • Deadly force should only be used in response to a hostile act or a demonstration of hostile intent. Deadly force is defined as force that causes or has a substantial risk of causing death or serious bodily harm.
  • Failure to comply with ROE may be punishable under the UCMJ.

ROE questions and concerns should be promptly elevated up the chain of command for resolution.

There are more parts to the Law of Armed Conflict as it is not just a series of treaties but an entire branch of international law. For more information and greater details to the parameters of LOAC, see the Law of Armed Conflict Deskbook.