If, on the other hand, either the United States is not in an armed conflict with al-Qaeda, or that conflict does not extend beyond Afghanistan, then two other areas of law come into play. One is the set of rules governing the resort to armed force (jus ad bellum), which holds that the use of force must be either authorized by the U.N. Security Council or exercised in self-defense as a necessary and proportionate response. Each targeted killing in Pakistan or elsewhere would thereby constitute a discrete resort to force, rather than subsumed under ongoing hostilities.
Outside the context of war, law enforcement norms as reflected in international human rights law, domestic law and constitutional due process may also apply, and the U.S. citizenship of prospective overseas targets starts to matter. Lethal force shifts from the first to last resort, to be utilized only in defense of life.
Through its white paper and speeches, the administration has offered an amalgamation of these standards, toggling between distinct doctrines in a hybrid approach that neglects to separate legal and policy limitations.
Such conflation carries dangers in itself by simultaneously setting the bar too high and too low. It offers an unduly restrictive conception of targeting in war, coupled with an underinclusive treatment of due process that appears to devalue its meaning as developed in constitutional jurisprudence. Consequently, the U.S. position is assailed by defense hawks, human rights advocates and libertarians all at once.
There are countless reasons why drone strikes may or may not be wise policy. The law is not determinative as to most of them.
Charles G. Kels is a major in the Air Force Reserve and an attorney for the Department of Homeland Security. Opinions expressed in this article are those of the author alone and do not necessarily reflect those of the departments of Homeland Security, Air Force or Defense.