Koh’s Legal Case for Drones

Aug. 1, 2010

The Obama Administration and International Law

Harold Hongju KohLegal Advisor, Department of State

American Society of International Law

Washington, D.C.

March 25, 2010


As the Afghan war has evolved, the Predator and other unmanned aircraft have become favorites of the Obama Administration, which views them as means for applying precision force. Critics of this practice mounted a major campaign to stigmatize such operations as illegal and illegitimate. In March, as criticism gathered force, State Department legal advisor Harold Hongju Koh advanced a strong defense of “targeted” drone operations against al Qaeda and its associated forces. The speech was all the more notable for the fact that Koh, a former Yale Law School dean, had earlier been a critic of such operations.

With respect to the subject of targeting, which has been much commented upon in the media and international legal circles, there are obviously limits to what I can say publicly. What I can say is that it is the considered view of this Administration—and it has certainly been my experience during my time as legal advisor—that US targeting practices, including lethal operations conducted with the use of unmanned aerial vehicles, comply with all applicable law, including the laws of war. …

In particular, this Administration has carefully reviewed the rules governing targeting operations to ensure that these operations are conducted consistently with law of war principles, including:

First, the principle of distinction, which requires that attacks be limited to military objectives and that civilians or civilian objects shall not be the object of the attack; and

Second, the principle of proportionality, which prohibits attacks that may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, that would be excessive in relation to the concrete and direct military advantage anticipated.

In US operations against al Qaeda and its associated forces—including lethal operations conducted with the use of unmanned aerial vehicles—great care is taken to adhere to these principles in both planning and execution, to ensure that only legitimate objectives are targeted and that collateral damage is kept to a minimum.

Recently, a number of legal objections have been raised against US targeting practices. While today is obviously not the occasion for a detailed legal opinion responding to each of these objections, let me briefly address four:

First, some 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.

Second, some have challenged the very use of advanced weapons systems, such as unmanned aerial vehicles, for lethal operations. But the rules that govern targeting do not turn on the type of weapon system used, and there is no prohibition under the laws of war on the use of technologically advanced weapons systems in armed conflict—such as pilotless aircraft or so-called smart bombs—so long as they are employed in conformity with applicable laws of war. Indeed, using such advanced technologies can ensure both that the best intelligence is available for planning operations, and that civilian casualties are minimized in carrying out such operations.

Third, some have argued that the use of lethal force against specific individuals fails to provide adequate process and thus constitutes unlawful extrajudicial killing. But a state that is engaged in an armed conflict or in legitimate self-defense is not required to provide targets with legal process before the state may use lethal force. Our procedures and practices for identifying lawful targets are extremely robust, and advanced technologies have helped to make our targeting even more precise. In my experience, the principles of distinction and proportionality that the United States applies are not just recited at meetings. They are implemented rigorously throughout the planning and execution of lethal operations to ensure that such operations are conducted in accordance with all applicable law.

Fourth and finally, some have argued that our targeting practices violate domestic law, in particular, the long-standing domestic ban on assassinations. But under domestic law, the use of lawful weapons systems—consistent with the applicable laws of war—for precision targeting of specific high-level belligerent leaders when acting in self-defense or during an armed conflict is not unlawful, and hence does not constitute “assassination.”