King of Battle, Your counsel is calling

Posted By: Katherine DePaul Professional Content ,

A High Mobility Artillery Rocket System live-fire demonstration is performed

during Exercise Talisman Sabre, July 8, 2019. (Senior Airman Ashley Maldonado/U.S. Air Force)

King of Battle, your counsel is calling

MAJ Katherine L. DePaul

With the rise of near-peer competition and a re-focus on large-scale combat operations (LSCO), the U.S. military cannot afford to have the King of Battle on the sidelines. This paper provides the Field Artillery with a discussion of the importance of legitimacy in modern conflicts, a refresher on the basic principles of the Law of Armed Conflict (LOAC), and discusses how these principles are incorporated within U.S. military doctrine and woven into our targeting methodologies. It concludes with examples of how to apply the LOAC in Field Artillery specific operations. By employing fires in accordance with the LOAC, the Field Artillery can maintain its position as the King of Battle and ensure long-range precision fires (LRPF) are the most attractive option for commanders tasked with winning our nation’s wars.

The LOAC is not an external, academic layer to be applied on top of military operations. Moreover, its principles have been part of the U.S. Army since its earliest conflicts and should be very familiar to the Field Artillery community already.1 Although international in origin, the LOAC’s basic principles of military necessity, distinction, proportionality, humanity and honor have been incorporated into U.S. domestic law and woven into U.S. military doctrine. The Department of Defense Law of War Manual; Field Manual 6-27, The Commander’s Handbook on the Law of Land Warfare; Army Regulation (AR) 350-1, Army Training and Leader Development (i.e., Table F-2, “The Soldier’s Rules”); and AR 27-23, Legal Review of Legality of Weapons under International Law, are just a few examples. The LOAC has also been baked into our targeting processes.

Recall the process of decide, detect, deliver and assess (D3A).2 The “decide” phase considers the principles of military necessity and distinction because only valid military objects are selected as targets. The “detect” phase relates to the principle of distinction because surveillance of the target should include an examination of the surrounding area for civilian and non-combatant personnel and objects. The “deliver” phase considers the principle of proportionality because weaponeering is employed to minimize collateral damage. Finally, the “assess” phase includes determining whether the strike resulted in any unexpected collateral damage and, if so, how such effects can be avoided or mitigated in future operations, both of which are proportionality considerations. Similarly, each of the five questions asked in the Collateral Damage Estimation (CDE) Methodology also relates to one or more LOAC principles.3 Consequently, understanding the LOAC - both what it requires and what it does not require - will help the Field Artillery correctly apply the D3A and CDE methodologies which, in turn, will enhance legitimacy in operations where fires are employed.

Legitimacy as a principle of war

“Legitimacy,” which joint doctrine recognizes as a principle of war, refers to the ability to “maintain legal and moral authority during operations.”4 Further, along with the unity of command and objective, legitimacy is recognized as being important in all operations.5 The importance of maintaining legitimacy in the conduct of operations can be seen with the current conflict with Iran. By using proxy forces to accomplish military objectives or using its forces but denying their involvement, Iran has succeeded in, at a minimum, delaying and potentially preventing attribution for many of its actions. For example, following the attacks on oil tankers near Fujairah, United Arab Emirates on May 12, 2019,6 and in the Gulf of Oman on June 13, 2019,7 the U.S. government and the international community were forced into a “tactical pause” as the world tried to determine who was responsible. Unless Iran or its proxies could be tied to the attacks, any use of force against Iran would likely have been be viewed as illegitimate.

The issue of legitimacy again surfaced when Iran attacked an unmanned U.S. drone. Although Iran admitted responsibility for the attack, it claimed the drone was operating inside its territorial borders.8 The United States disputed that claim, arguing the drone was operating in international airspace.9 The battle for legitimacy over the initial attack and potential response waged without either side winning clear victory. These incidents highlight just a few of the many ways in which the principle of legitimacy is being employed in the current environment where Field Artillery units operate.10

The Law of Armed Combat

Because lawfulness confers legitimacy, adhering to the LOAC will enable commanders to maintain legitimacy during operations. The basic principles of the LOAC are a military necessity, distinction, proportionality, humanity and honor. The LOAC should not be confused with rules of engagement (ROE) which are a commander’s rules for the use of force based on operational, political and legal considerations. Unlike the basic principles of the LOAC, which do not change regardless of the operating environment, ROE is theater-specific and can change as operational, political and legal considerations change. As professional warfighters, Field Artillery planners must be familiar with and accurately apply the LOAC concepts, not only because they are legally obliged to do so, but to ensure partner nations and U.S. citizens view their operations as legitimate.

Unfortunately, some mistakenly believe following the LOAC is akin to “fighting with one hand tied behind your back.” This thinking shows a fundamental misunderstanding of the LOAC for three reasons. First, the LOAC is primarily aimed at protecting civilian and noncombatant personnel and objects who, by their very definition, are not directly participating in hostilities or contributing to the enemy’s warfighting functions. Thus, attacking such persons or objects wastes valuable and often limited resources without accomplishing the mission. Second, civilians and noncombatant personnel or objects who directly participate in hostilities lose their protected status and can be attacked. Finally, the incidental death or destruction of civilian and noncombatant persons or objects during an armed conflict is not a per se LOAC violation; as noted below, such actions are only prohibited if the resulting collateral damage was excessive in relation to the concrete and direct military advantage gained by the attack.

When applied correctly, adhering to the LOAC enhances the targeting process by placing fires and effects upon valid military targets. Failure to do so, however, risks the Field Artillery being sidelined in future battles as commanders pursue other options that can meet mission requirements while also maintaining legitimacy.

The principles of the Law of Armed Conflict

First, military necessity is defined as the principle that justifies the use of all measures needed to defeat the enemy as quickly and efficiently as possible that are not prohibited by the LOAC.11 Military necessity does not require the use of minimum force necessary to accomplish the mission; such an erroneous interpretation would prolong conflicts and increase suffering.12

Second, the principle of distinction obligates parties to a conflict to distinguish between military objects and civilian and noncombatant personnel13 and objects. A “military object” is an object by which its nature, location, purpose or use makes an effective contribution to military action and whose total or partial destruction, capture or neutralization, under the circumstances at the time, offers a definite military advantage.14 Examples of military objects include enemy radars and integrated air defense systems (IADS), both typical targets of artillery fires.

The third principle, proportionality, requires commanders to refrain from attacks in which incidental harm to civilian and noncombatant personnel and objects would be “excessive” in relation to the concrete and direct military advantage expected to be gained.15 This principle also requires commanders to take “feasible precautions” in planning and conducting attacks to reduce the risk of harm to civilian and noncombatant persons and objects.16 Proportionality does not impose obligations intended to reduce the risk of harm to enemy personnel or objects. Instead, protecting civilian and noncombatant personnel and objects is its primary focus. In making proportionality assessments, commanders are expected to act reasonably based on the information known at the time.

Critically, the principle of proportionality under the LOAC should not be confused with the principle of proportionality in self-defense. While the principle of proportionality under the LOAC seeks to reduce the risk of harm to civilians and noncombatant personnel and objects, the principle of proportionality under self-defense restricts the use of force applied to a military object to that which in nature, duration and scope is necessary to respond decisively. The distinction between proportionality under the LOAC and proportionality in self-defense is highlighted in the practical application section.

The fourth principle, humanity, prohibits the intentional infliction of unnecessary violence against the enemy.17 Of course, violence is often necessary during war. This principle only precludes gratuitous violence which is not needed for mission accomplishment and is specifically intended to cause unnecessary suffering. For example, white phosphorous is a lawful weapon. However, like any other lawful weapon, it must not be used in a manner intended to cause unnecessary suffering such as burning enemy personnel for the purpose of causing maximum suffering when other equally effective weapons were available for employment.

Honor is also a foundational principle of the LOAC and an Army Value. Honor requires a certain amount of fairness and mutual respect between opposing forces. In keeping with the concept of honor, the Department of Defense (DoD) Law of War Manual requires members of the DoD to comply with the LOAC during all armed conflicts, however such conflicts are characterized and in all other military operations.18 Further, honor also requires adherence to the LOAC regardless of the enemy’s level of compliance.

Soldiers from the 2nd Battalion, 300th Field Artillery Regiment, Wyoming Army National Guard, fire

a High Mobility Artillery Rocket System June 23, 2020, at Camp Guernsey Joint Training Center.

(1LT Andrew Wagnon/Wyoming Army National Guard)

Practical application

Position Artillery Area (PAA) selection – feasible precautions

Following Iran’s strike on the U.S. drone, suppose a High Mobility Artillery Rocket System (HIMARS) crew had been ordered to a PAA to employ LRPF against the Iranian radars and IADS used in the attack. What LOAC considerations should be applied to PAAs? When determining PAAs, commanders and staff should consider their obligations to take “feasible precautions” to distinguish themselves from and avoid harm to civilian and noncombatant personnel and objects. For example, artillery crews are subject to attack by counter-fire. Accordingly, PAAs should not be placed near populated areas, cultural sites or other civilian and noncombatant structures if such placement would subject those persons or objects to enemy counter-fire. Once PAAs are established, commanders and staff must assess the PAAs to verify whether any protected persons or objects have moved into the area. If so, the staff should analyze whether the PAA could be moved without unacceptable risk to the mission or the force, a determination which ultimately will be made by the commander. It is important to remember that “feasible precautions” do not require that everything possible is done to avoid harm to civilian or noncombatant personnel or objects. Moreover, commanders must always consider the operational risk and risk of harm to the force of employing such precautions.

Cluster munitions - distinction

Arrival at the PAA with a known target is only part of processing a firing mission; selection of an appropriate munition is critical. What LOAC considerations are there in munition selection? The U.S. is not a party to the Convention on Cluster Munitions. However, the DoD Policy on Cluster Munitions has restricted the employment of cluster munitions with an unexploded ordinance (UXO) greater than one percent to the combatant commander.19 The concern with unexploded ordinance is the principle of distinction – a UXO cannot distinguish between civilian and noncombatant personnel and objects. Artillery units in a deployed environment must consider whether the target set, in this scenario radars and IADS, requires the employment of cluster munitions with a UXO producing rate greater than one percent or whether the target set can be serviced with an alternative munition that will achieve the desired effect. If planners cannot articulate why this type of cluster munition should be employed despite the concerns about distinction or find a satisfactory alternative that can meet mission requirements, cluster munitions, and the artillery that delivers them, will not be an attractive option.

Soldiers from 1st Battalion, 182nd Field Artillery, Michigan Army National Guard,

fire a rocket from a High Mobility Artillery System during the Northern Strike

exercise at Camp Grayling, Mich. (CPT Joe Legros/Michigan Army National Guard)

Weaponeering – proportionality

Following Iran’s attack on the U.S. drone, the president tweeted that he would have responded with force, however, the option he was provided would have resulted in the death of 150 people.20 The president concluded a strike that would kill 150 people was “not proportionate to shooting down an unmanned drone.”21 Consequently, the president decided against a kinetic strike against Iranian radars and IADS, instead opting for a non-lethal cyber-attack that targeted Iranian missile launch systems.22 It is not clear from the news reporting whether any of the 150 people were civilians and/or noncombatants. Assuming for illustration purposes that the 150 people were civilians and/or noncombatants, the president may have determined their deaths would have been excessive in relation to the concrete and direct military advantage to be gained, and thus, disproportionate under the LOAC. Alternatively, assuming for illustration purposes that the 150 people were Iranian military members who participated in the attack, the president could have determined their deaths were not necessary to respond decisively to the downed drone and thus, a violation of the principle of proportionality under self-defense. Regardless of whether the strike failed proportionality under the LOAC or proportionality under self-defense, kinetic options, of which LRPF may have been available, were ruled out because the commander-in-chief was not presented with a course of action he assessed as legitimate. As shown by this example, fires planners must be able to provide commanders with options that will accomplish the mission with the least amount of coll-ateral damage. Otherwise, commanders are obligated to look elsewhere.


Fighting lawfully enhances legitimacy, a principle of war that is increasingly important in modern conflicts. As the multi-domain battlefield becomes more complex and other nations improve their capabilities, accurate delivery of LRPF will be critical to winning LSCO against near-peer competitors. By employing fires in accordance with the LOAC, which is already baked into our targeting methodologies, the Field Artillery community can maintain its position as the King of Battle and ensure LRPF is the most attractive option for the commanders. Because of their expertise in military law, judge advocates are uniquely positioned to enable commanders to achieve legitimacy through timely, accurate and principled counsel on the application of the LOAC to Field Artillery operations. So Redlegs, if confronted with a complex question involving the LOAC, call your counsel before you call for fire!23

MAJ Katherine L. DePaul served as the brigade judge advocate for the 18th Field Artillery Brigade located at Fort Bragg, N.C. from 2018 through 2020. During this time, MAJ DePaul deployed with the brigade to Camp Redleg. She previously, served as a legal assistance attorney, trial counsel, administrative law attorney and defense appellate attorney. Her next assignment is as a student at the U.S. Army Command and General Staff College at Fort Leavenworth., Kan. She attended law school at Temple University, the Beasley School of Law in Philadelphia, Pa.

1 General Orders No. 100: The Lieber Code, Instructions for the Government of Armies of the United States in the Field, (e.g., Art. 37 provides, “The United States acknowledge and protect, in hostile countries occupied by them, religion and morality; strictly private property; the persons of the inhabitants, especially those of women: and the sacredness of domestic relations. Offenses to the contrary shall be rigorously punished.”).

2 Army Training Publication (ATP) 3-60, TARGETING, May 2015, Chapter 2.dam

3 First, has positive identification of the target been established (military necessity/distinction)? Second, are there collateral objects, including noncombatant personnel, CBR plume hazards, or significant environmental concerns within the effects range of the weapon selected to attack the target (distinction)? Third, can damage to those collateral objects be mitigated by engaging the target with a different weapon or method of employment, yet still accomplish the mission (proportionality)? Fourth, if not, how many civilian and noncombatant casualties will the attack be expected to cause (proportionality)? Fifth, would the collateral effects exceed the commander’s guidance, requiring elevation of the strike decision (proportionality)? Overall, the methodology is designed to ensure our forces attack only lawful military objects and to avoid or minimize collateral damage while still accomplishing the mission.

4 Joint Publication 3-0, JOINT OPERATIONS, Appendix A, A-4 (17 January 2017, Incorporating Change 1, 22 October 2018). The twelve principles of war are objective, offensive, mass, maneuver, economy of force, unity of command, security, surprise, simplicity, restraint, perseverance, and legitimacy. Id. at ix.

5 Id. at A-1.

6 Vivian Yee, Claim of Attacks on 4 Oil Vessels Raises Tensions in the Middle East, THE NEW YORK TIMES (May 2019),

7 John Bacon, Pompeo: Iran Responsible for Attack on Oil Tankers in Gulf of Oman, USA TODAY (June 2019),

8 Michael D. Sheer, et. al., Strikes on Iran Approved by Trump, then Abruptly Pulled Back, THE NEW YORK TIMES (June 2019),

9 Id.

10 An additional example is both the United States’ and Iran’s repeated public statements that each seeks to avoid war, but will defend its interests if threatened by the other. Moreover, both blame the other as the reason for heightened tensions. Associated Press, The Latest: Top Officials Say US Doesn’t Want War With Iran, US NEWS (May 2019), (Secretary of State, Michael Pompeo, has said, “We fundamentally do not seek war with Iran” while adding, “We have also made clear to the Iranians that if American interest are attacked, we will most certainly respond in an appropriate fashion); Steve Inskeep and Bobby Allyn, NATIONAL PUBLIC RADIO (June 2019), (Iran’s ambassador to the United Nations sent letters to the U.N. Security Council claiming it acted in lawful self-defense by attacking the U.S. drone, reiterating it “does not seek war.”).

11 DEPARTMENT OF DEFENSE LAW OF WAR MANUAL [Hereinafter DOD LOWM], para. 2.2, June 2015 (Updated December 2016).

12 Field Manual 6-27, THE COMMANDER’S HANDBOOK ON THE LAW OF LAND WARFARE, 07 August 2019, para. 1-24.

13 “Noncombatant personnel” include military medical and religious personnel. See DOD LOWM para. 2.5.1.

14 Id. at para. 2.5.

15 Id. at para. 5.10.

16 Id. at para. 5.10.1.

17 Id. at para. 6.6.1.

18 Id. at para.

19 DoD Policy on Cluster Munitions (2017) available at

20 Lolita C. Baldor and Deb Reichman, Trump Says He Decided Retaliation Attack on Iran Not Proportional, LAS VEGAS REVIEW-JOURNAL (June 2019),

21 Id.

22 Julian E. Barnes and Thomas Gibbons-Neff, U.S. Carried Out Cyberattacks on Iran, THE NEW YORK TIMES (JUNE 2019),

23 This is not to suggest that commanders must consult with an attorney prior to making every decision. Such a practice is not necessary, nor is it desirable. However, judge advocates, like any other staff member, have a valuable role in the commander’s decision making process, particularly with respect to application of the LOAC.