Part III: Do U.S. Drone Strikes Adhere to the Law of War?
Targeted strikes, like any other military attack by U.S. armed forces, must adhere to recognized principles of the law of war.
The principles of the law of war are relevant to any armed attack, whether a Marine sniper firing on a distant combatant, Army attack helicopters striking an armored column, or a Navy warship targeting a bunker with a cruise missile.
The fundamental principles commonly discussed in the debate over drone strikes are necessity, distinction, and proportionality.
Necessity and Distinction
Under the law of war…an armed attack must adhere to the principles of necessity and distinction. A combatant must target only other combatants (the principle of “distinction”) and targeting such combatants must be considered militarily necessary to bring about the submission of the enemy (the principle of “necessity”).
The principle of distinction requires that only combatants and military objectives be targeted. While civilian casualties may occur during hostilities, intentionally targeting civilians is forbidden unless they “directly participate in hostilities.” The principle of necessity requires that an attack against an enemy provide the attacker with a “definite military advantage” for the purpose of effecting the “complete submission of the enemy as soon as possible.”
In a traditional armed conflict, decisions regarding whether a target satisfies the tests of distinction and necessity are straightforward. Enemy tanks, artillery, aircraft, warships, and infantry are obviously non-civilian in nature and almost always qualify as necessary to destroy in order to bring about the enemy’s submission. The conflict against al-Qaeda is less traditional because U.S. targeting analysis in the context of drone strikes focuses almost exclusively on individual enemy combatants—the commanders, lieutenants, facilitators, and other al-Qaeda operatives—rather than airfields, munitions plants, and the like. Moreover, al-Qaeda combatants regularly dress as civilians, pose as non-combatants, operate from civilian areas, and even use civilians and other protected persons and objects as shields.
Responding to allegations that targeting individual commanders is somehow unlawful under international law, State Department Legal Adviser Harold Koh stated:
[S]ome have suggested that the very act of targeting a particular leader of an enemy force in an armed conflict must violate the laws of war. But individuals who are part of such an armed group are belligerents and, therefore, lawful targets under international law. During World War II, for example, American aviators tracked and shot down the airplane carrying the architect of the Japanese attack on Pearl Harbor, who was also the leader of enemy forces in the Battle of Midway. This was a lawful operation then, and would be if conducted today. Indeed, targeting particular individuals serves to narrow the focus when force is employed and to avoid broader harm to civilians and civilian objects.
In any event, press reports indicate that the Obama Administration goes to great lengths in determining that an individual al-Qaeda operative is a non-civilian, militarily necessary target before qualifying the operative as subject to lethal force.
The publicly available information on the Obama Administration’s targeting analysis indicates that the U.S. military and CIA adhere to the principles of distinction and necessity. For example, in an April 2012 speech, counterterrorism adviser John Brennan described how armed drones are particularly well suited to carry out strikes against al-Qaeda militants while respecting the principle of distinction:
Targeted strikes conform to the principle of distinction, the idea that only military objectives may be intentionally targeted and that civilians are protected from being intentionally targeted. With the unprecedented ability of remotely piloted aircraft to precisely target a military objective while minimizing collateral damage, one could argue that never before has there been a weapon that allows us to distinguish more effectively between an al-Qaida terrorist and innocent civilians.
Reports in The New York Times and The Washington Post indicate that military, intelligence, and Administration officials oversee a rigorous process to determine whether a particular individual is necessary to target.
Over time the process for selecting targets evolved into a “next generation” targeting list known as the “disposition matrix.” The National Counterterrorism Center (NCTC) developed the matrix to “augment” the separate, but overlapping lists developed by the Pentagon and the CIA, resulting in “a single, continually evolving database in which biographies, locations, known associates and affiliated organizations are all catalogued.” The targeting criteria focus on al-Qaeda’s operational leaders and key facilitators, and the names are submitted to a panel of National Security Council officials for approval. Targeting lists are reviewed regularly at meetings at NCTC headquarters attended by officials from the Pentagon, State Department, and CIA.
Even if an al-Qaeda operative is properly identified, placed in the “disposition matrix” and deemed militarily necessary to target, the law-of-war principle of “proportionality” must also be satisfied for a strike on that operative to be considered lawful. The principle of proportionality requires belligerents to take care to minimize harm to innocent civilians during an armed attack.
Specifically, the principle of proportionality prohibits attacks on military targets where the expected harm to civilians (for example, within the blast radius of an explosion) is excessive in comparison to the military advantage expected to be gained from the attack.
Senior Obama Administration officials, including State Department Legal Adviser Harold Koh, Attorney General Eric Holder, and CIA General Counsel Stephen Preston have regularly affirmed in public speeches that the United States adheres to the principle of proportionality when striking al-Qaeda targets.
For example, John Brennan stated:
Targeted strikes conform to the principle of proportionality, the notion that the anticipated collateral damage of an action cannot be excessive in relation to the anticipated military advantage. By targeting an individual terrorist or small numbers of terrorists with ordnance that can be adapted to avoid harming others in the immediate vicinity, it is hard to imagine a tool that can better minimize the risk to civilians than remotely piloted aircraft.
By its nature, adherence to the principle of proportionality must be determined on a case-by-case, attack-by-attack basis. In the context of drone strikes, targeting analyses and decisions accounting for the principles of distinction and necessity are reportedly made by military and intelligence officials when al-Qaeda operatives are placed on the disposition matrix, likely well in advance of an actual attack. Factors concerning a determination of proportionality, by contrast, may usually be considered and weighed only after the target has been physically located and the surrounding environment assessed for potential civilian casualties.
That said, by their nature, drone strikes are designed to be precise attacks on individual targets of military significance as opposed to indiscriminate attacks, such as carpet bombing a military installation situated alongside civilian buildings or an artillery barrage on an armored column travelling through an area known to be populated by civilians. That is not to say that drone strikes have not caused civilian casualties. They have. However, no evidence indicates that U.S. armed forces or CIA officers, in carrying out targeted strikes, have disregarded the principle of proportionality.
In sum, no evidence indicates that U.S. targeted drone strikes violate the law of war principles of necessity, distinction, or proportionality, much less in any intentional, systematic, or chronic manner. To the contrary, the use of drones, which can loiter over a target for hours waiting for the optimal moment to strike, is a particularly effective method of eliminating individual terrorist threats while adhering to the law of war. The publicly available evidence indicates that the U.S. government chooses its targets carefully and regularly reassesses the threats posed by those targets. While there is no guarantee that all civilian casualties can be eliminated, the use of drone strikes, as opposed to an armed invasion or use of large munitions, vastly minimizes the exposure of civilians.
Steven Groves is Bernard and Barbara Lomas Senior Research Fellow in the Margaret Thatcher Center for Freedom, a division of the Kathryn and Shelby Cullom Davis Institute for International Studies, at The Heritage Foundation.