Armed Conflict Foreign Relations & International Law

Warnings to Civilians Directly Participating in Hostilities: Legal Imperative or Ethics-based Policy?

Butch Bracknell
Sunday, November 29, 2015, 10:03 AM

American and allied forces efforts in the fight against ISIL have recently focused on disrupting the terrorist group’s primary source of revenue: oil production and transportation. The New York Times reports that ISIL generates approximately $40 million each month in oil exports, and uses those funds to further terror activities at home and abroad.

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American and allied forces efforts in the fight against ISIL have recently focused on disrupting the terrorist group’s primary source of revenue: oil production and transportation. The New York Times reports that ISIL generates approximately $40 million each month in oil exports, and uses those funds to further terror activities at home and abroad.

The Times notes the Obama administration has, heretofore, “balked at attacking the Islamic State’s fleet of tanker trucks – its main distribution network – fearing civilian casualties.” Notably, the same article acknowledges that there have been numerous American “airstrikes against oil refineries and other production facilities in eastern Syria.” That distinction had been difficult to grasp, as presumably targeting refineries risks similar civilian causalities. Whatever the underlying rationale, the Administration has since changed course and last week targeted hundreds of oil-transport trucks, destroying 116 of the approximately 1,000-vehicle fleet. According to the Times:

To reduce the risk of harming civilians, two F-15 warplanes dropped leaflets about an hour before the attack warning drivers to abandon their vehicles, and strafing runs were conducted to reinforce the message.

The area where the trucks assemble in Syria has been closely monitored by reconnaissance drones. As many as 1,000 trucks have been observed there, waiting to receive their cargo of illicit oil. … [During the bombing t]he pilots saw several drivers running to a nearby tent and did not attack them, an American official said, and there were no immediate reports of civilian casualties.

The decision to drop the warning leaflets raises an interesting question: Was the decision to warn based on policy or legal considerations?

There are a number of policy reasons to warn in advance of this kind of an attack. First, providing warnings might mitigate the consequences of a mistake. Intelligence is not infallible, and the U.S. could, theoretically, mistakenly target an oil truck engaged in ordinary commerce and not supporting or otherwise benefiting ISIL. By warning the driver, the U.S. constrains the risk of mistake to the wrongful destruction of civilian property—a claim it can resolve with money—and avoids politically-costly and tragic civilian casualties.

Second, warning truck drivers demonstrates that the U.S. values human life, a particular contrast to the savagery of ISIL. Many oil truck drivers have been pressed into involuntary service and are merely protecting and supporting their families. Warning these individuals not only spares their lives, it serves psychological messaging goals as well. The oil truck drivers, returning to ISIL commanders with leaflets in hand, reinforce that American forces remain in total control of the skies.

And these advantages come with little downside. Considering ISIL’s virtually non-existent anti-aircraft capabilities, the practice of warning imposes little risk to U.S. personnel. Furthermore, it does not increase a likelihood of mission failure, so long as the strikes are announced when ISIL cannot scatter or hide the trucks—for example on an open desert road. In total, the decision to warn oil truck drivers represents sound military and strategic policy. Killing civilians—whatever the lawfulness of the strike or individual targeted—only serves the ISIL narrative. That said, it is important to note that warning the drivers is purely a question of policy and these warnings are not required by the laws of armed conflict.

First, consider that, under the laws of armed conflict, oil and fuel trucks that support ISIL military capacity are legitimate targets regardless of location. It is not relevant whether the trucks are travelling to a port to offload cargo for revenue-producing export or whether they are bound for the “front lines” to directly contribute to ISIL military operations. So long as U.S. and allied forces can demonstrate “military necessity” to destroy the tankers, they constitute legitimate military targets. The discussion here centers on the truck driver’s themselves; the law of armed conflict is rightly more protective of people than it is of property.

So, what is the status—and corresponding legal obligations—of individuals driving ISIL oil and fuel trucks?

Lawful Combatants

In the case of truck drivers who qualify as lawful combatants, the law of armed conflict unequivocally permits the intentional targeting of the drivers without warning. The lawfulness of this targeting is based on an individual’s status as a lawful combatant—a soldier or fighter holding himself out as a soldier—not his or her activities. As a general matter, the law of armed conflict permits an armed force (lawful combatants) to engage another armed force (opposing lawful combatants) engaged in combat operations, where the armed forces operate under responsible command, wear uniforms, and carry arms openly. ISIL members who meet these criteria are lawful targets, whether or not they are driving fuel trucks.

In fact, lawful combatants need not be in the middle of conducting active operations to be targetable; they can be in a bivouac site or assembly area, in a convoy leaving the battlefield, or area effectively off the battlefield. Lawful combatants may be targeted while eating, sleeping, playing billiards, and driving oil trucks. Furthermore, the fact that individual truck drivers may have been forced or coerced into ISIL service might present a moral issue, but it does not implicate legal considerations. Under the laws of armed conflict, militaries are permitted to target an opposing force’s conscripted soldiers. [Note: Potential prohibitions in international human rights law are beyond the scope of the present discussion.]

Directly Participating in Hostilities

Conversely, civilians may not generally be made the object of an armed attack. However, this general protection extends only to civilian non-combatants. Article 51(3) of the 1977 Additional Protocol to the Geneva Conventions notes civilians directly participating in hostilities may also be targeted while participating in an activity that contributes to the combat efforts of lawful combatants – performing auxiliary functions such as manning a radar station, distributing pay to soldiers, or driving fuel trucks. Targeting civilians directly participating in hostilities requires scrutiny of their conduct, not merely their status.

A significant number of fuel truck drivers will not meet the criteria of lawful combatants. However, their conduct driving the trucks clearly constitutes civilians directly participating in hostilities. Furthermore, there is little legal distinction between targeting fuel trucks driving in direct support of combat operations – for example, from a logistics depot to front lines of a conflict to refuel combat vehicles – and those driving in support of economic activities supporting the ISIL war effort. In both cases, the civilian is directly participating in hostilities. The International Committee of the Red Cross (ICRC) has laid out a three-part test for determining when civilians are directly participating in hostilities:

(1) The act must be likely to adversely affect the military operations or military capacity of a party to an armed conflict, or alternatively, to inflict death, injury, or destruction on persons or objects protected against direct attack (threshold of harm);

(2) There must be a direct causal link between the act and the harm likely to result either from that act, or from a coordinated military operation of which that act constitutes an integral part (direct causation); and

(3) The act must be specifically designed to directly cause the required threshold of harm in support of a party to the conflict and to the detriment of another (belligerent nexus). In other words, the civilian’s activity must generate military harm against an opposing force or protected civilians; the civilian’s act must directly cause the harm; and the civilian’s act must be specifically designed to cause the harm. The ICRC posits this test represents the definitive state of the law in this area, though individual states may distinguish the test on the margins.

Under these criteria, the analysis of an attack on a fuel convoy moving from a logistics support area to refuel ISIL trucks or armoured vehicles conducting military maneuvers is straightforward. In that case, ISIL military vehicles—with guns to kill opposing forces and terrorize civilians—cannot operate without fuel, and therefore, fuel transportation adversely affects the party opposing ISIL. There is a clear causal link between refuelling ISIL combat vehicles and the delivery of military effects on opposing forces or civilians. Moreover, the act of refuelling the ISIL vehicles is presumptively purposeful; in other words, there is no other reason to do it than to enable ISIL combat operations.

The three-part analysis is more nuanced when examining strikes against oil tankers that are moving fuel to generate economic benefits for ISIL and not to directly enable combat operations. While the nexus and causation are slightly more attenuated, they warrant the determination that the civilian drivers are directly supporting ISIL combat activity and can, therefore, be targeted. This is particularly true given the temporal and geographical proximity of the financial generation activity to ISIL’s military units and operations. Just as the ISIL vehicles do not drive without fuel, the fuel does not reach them without the closely-associated economic activity that generates the revenue to enable ISIL combat operations (threshold of harm). The generation of this income directly enables ISIL combat activities (direct causation), and the generation of the income is specifically designed to enable ISIL operations (belligerent nexus). Thus, targeting oil tankers transporting fuel to generate revenue is virtually identical to targeting those moving fuel to ISIL on the battlefield.

This analysis is generally consistent with the U.S. view, as expressed in Paragraph 5.9 of the DoD Law of War Manual. However, the U.S. might also take the alternative view that oil truck drivers who voluntarily support ISIL can be lawfully targeted based on their membership in a Non-State Armed Group (see para 5.8.3 of the DoD Law of War Manual).

Importantly, the analysis regarding direct participation in hostilities should not be confused with the principle of distinction. American and allied forces have the burden of distinguishing between ordinary economic activity – to the extent any still exists in Syria – and economic activity (transportation of oil) designed to benefit ISIL. In honoring that principle, American and allied forces may not target oil tankers based merely on proximity. Rather, they must have reliable intelligence that the specific oil tankers are, in fact, ISIL-affiliated and that they generating funds to enable ISIL combat operations against opposing forces and civilians. However, where such distinction is satisfied, ISIL oil tankers may be treated as military targets consistent with the laws of armed conflict.

In summary, it is unclear exactly why U.S. forces elected to warn truck drivers prior to the recent air strikes. That decision may reflect an admirable general regard for human life and show care to avoid civilian causalities where possible. Or perhaps, it is intended as a signal to ISIL regarding the overwhelming military capacity they face and is designed to leave witnesses to recount the tale of U.S. military might. But to be sure, so long as U.S. and allied military units establish the trucks benefit ISIL military capacity, there is no legal obligation to warn the drivers. And those closely tracking the U.S. efforts against ISIL should not assume the law requires more than it does.


Butch Bracknell is a retired Marine officer, an international law professional, a former international security fellow at The Atlantic Council of the United States, a member of the Truman National Security Project, and fellow at the Sorensen Institute for Political Leadership. These opinions are his own and may not be attributed to any organization or institution.

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