Q. Is the use of armed drones legal under international law?
There is no legal prohibition against the use of armed drones. Although there are movements to ban weaponized drones through an anti-drone treaty, which will be discussed in subsequent sections, international institutions have generally regarded drones in the spirit of saying that "drones don't kill people, people kill people." In other words, international law has essentially considered drones as another platform. Just as an F-16 is legal as long as it is used in accordance with international law, so too is a drone.
The international legal questions that arise with drones are not as much with the technology itself but rather how the drones are used. And the questions about how armed drones are used has been raised most saliently in the context of the United States, which is reasonable given that it has been the country to use armed drones most frequently. Insofar as state practice sets precedents in terms of how other states in the future use drones,69 examining these cases of armed drone strikes in terms of international legal compliance is quite reasonable. Indeed, CIA Director John Brennan has remarked on how these principles could lay the foundation for how other nations use drones. He said that the administration's use of drones is "establishing precedents that other nations may follow, and not all of them will be nations that share our interests... . If we want other nations to use these technologies responsibly, we must use them responsibly. We cannot expect of others what we will not do ourselves."70
Critics have raised a number of legal and ethical questions about the United States' use of armed drones in combat. One set of questions deals with whether drone strikes comply with the recourse to force under international law (jus ad bellum, which means "right to war"). Indeed, the jus ad bellum concerns are about "the parameters of the war in which they're being used"—that is whether the United States is authorized to engage in armed attacks at all—rather than the technology itself.71 Once a state has resorted to force, the vehicle through which states use force is less relevant than whether that force is proportional and distinguishes between civilian and combatant, an issue addressed later.
Under the UN Charter, there are two main circumstances under which states can use force: under Article 51, which is the right to collective or individual self-defense, and with a UN Security Council authorization. Otherwise, Article 2 (4) of the UN Charter proscribes intervention in other states' territories.
One view of drone strikes suggests that they are legal in active battlefields such as Afghanistan, Iraq, and Libya but also in places such as Pakistan, Yemen, and Somalia. This view has suggested that the United States is in fact engaged in a non-international armed conflict (NIAC) with the Taliban, Al-Qaeda, and its associates, and can target these forces where they exist. The supportive view also points to drone strikes as consistent with the principle of anticipatory self-defense, which customary international law interprets as a threat that is "instant, overwhelming, and leaving no choice of means, and no moment of deliberation." In its white paper on targeting suspected terrorists, the United States points to the importance of targeting imminent threats that are outside " 'hot' battlefields."72
A more restrictive view of this self-defense claim would say that the use of drones for targeting suspected terrorists outside "hot" battlefields such as Afghanistan violates the jus ad bellum principle of international law. Legal scholars such as Mary Ellen O'Connell dispute that the United States is engaged in an armed conflict with Pakistan, Yemen, and Somalia insofar as the hostilities are sporadic rather than a case of ongoing conflict, which would rule out the legality of drone strikes in these countries even if those countries consent.73 More problematically, questions arise about whether the targets are compatible with anticipatory self-defense. Many of the targets have been lower-1 evel foot soldiers—j ust 2% are "high-1 evel targets"— who are "neither presently aggressing nor temporally about to aggress."74
Another line of critique about the use of drones in combat focuses on jus in hello, generally with respect to treatment of civilians and in particular whether combat drones are compatible with the principles of distinction and proportionality. The origins of both principles come from the just war tradition, which provided a set of philosophical and ethical guidelines for how actors would conduct themselves in conflict. These guidelines were later codified into the protocols that form the basis of international humanitarian law, which expects actors to discriminate between civilians and combatants, targeting the latter for military advantage and minimizing the damage to the former.75
According to the principle of distinction, actors are prohibited from directing their attacks against civilians. According to Article 48 of the Protocol Additional to the Geneva Convention (AP I), "In order to ensure respect for and protection of the civilian population and civilian objects, the Parties to the conflict shall at all times distinguish between the civilian population and combatants and between civilian objects and military objectives and accordingly shall direct their operations only against military objectives."76 Beyond this provision, Article 57 of AP I requires that states "take all feasible precautions in the choice of means and methods of attack with a view to avoiding or in any event minimizing incidental loss of civilian life, injury to civilians and damage to civilian objects."77
Building on the principle of distinction, the principle of proportionality suggests that the anticipated military gain of a strike must exceed the anticipated damage to civilians and their property. Article 51 (5) (b) of AP I proscribes "an attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated."78 As the former Prosecutor of the International Criminal Court, Luis Moreno- Ocampo, suggested, "the death of civilians does not in itself constitute a war crime." It must be intentional and must exceed the anticipated military advantage.
Members of the policy and legal community have debated at length whether drone strikes meet the principles of distinction and proportionality under jus in hello. As Max Boot states, "[t]he US military operates a bewildering array of sensors to cut through the fog of war."79 Military documents themselves point to the way that technology facilitates the kind of awareness that would help comply with international legal principles. The military's Joint Vision 2010 notes that "in all operations technological advances ... allow them [the warfighters] to make better decisions."80 The precision capabilities of an armed Predator or Reaper that can loiter over targets and carry precision munitions are an improvement over earlier alternatives such as carpet-bombing. Drones may also be an improvement over alternatives, such as the use of ground forces or air strikes. In his collection of data from drone strikes, Avery Plaw suggests that civilian fatalities from the use of drones are comparatively lower than either non-drone US operations or Pakistani ground operations in FATA, suggesting that drone strikes are more proportional than the alternatives, or at least less disproportional. He concludes that "a fair-minded evaluation of the best data we have available suggests that the drone program compares favorably with similar operations and contemporary armed conflict more generally."81
Other accounts of US targeting are less charitable in terms of its compliance with the laws of war. Technology, in the form of better sensors, may produce intelligence that can help inform high-stakes decisions, which otherwise could be too risky without sufficient surveillance information. Additionally, the development in the precision of weapons has proved more effective in both hitting the designated target and causing less incidental damage. However, it cannot make the subtle distinctions necessary for adjudicating the fine line between a civilian and a combatant. This exposes the problem with assertions made by individuals such as CIA Director John Brennan that "one of the things President Obama has insisted on is that we're exceptionally precise and surgical in terms of addressing the terrorist threat." The implication is that precision means distinction and proportionality in hitting the terrorists and sparing damage to others, erroneously implying that technology can be the last word on judgments about context and identity.
Inherent in these judgments is the often-subjective question of who is a combatant and therefore a legal target and who is a civilian and therefore not a legal or legitimate target. As earlier sections suggest, drone strikes have indeed killed a number of civilians, but the percentages vary widely. One of the reasons why these accounts and percentages vary widely is because of fluid interpretations of who is defined as an illegal civilian target and who is defined as a legal combatant target, creating challenges in terms of ascertaining exactly who is a combatant and who is a civilian. Part of the problem resides in the ambiguity of Article 4 of the Geneva Conventions, which designates an individual as a combatant in part by "having a fixed distinctive emblem recognizable at a distance." The 1977 AP I states that "civilians shall enjoy the protection afforded by this section, unless and for such time as they take a direct part in hostilities."82
Conventional wars such as World War II made these criteria quite clear, since combatants were generally wearing uniforms. Modern unconventional conflict creates situations where combatants are not clearly identifiable based on emblems, and are often oscillating between direct and indirect participant and civilian. The commingling makes it difficult to discern legitimate combatants from protected civilians.83 Applying the standard to counterterrorist situations is therefore quite fraught with difficulties. The International Committee of the Red Cross has sought to offer clear guidance on the difference between direct and indirect participation, but even their legal experts have had challenges coming to a consensus. As the Israeli High Court of Justice's Judgment on Targeted Killings reported, "the notion of direct participation in hostilities is complex, emotive, and still inadequately resolved."84 Its own view is that the "direct" character of the part taken should not be narrowed merely to the person committing the physical act of attack but should also include people in the business of intelligence and transportation of those who do carry out those attacks. By this measure, almost anyone in a community could wittingly or unwittingly be in a position to be considered as having a direct involvement in hostilities.85
That the definition can be quite subjective explains in part the wide variation among accounts of civilian casualties, as discussed earlier. For example, many cases of individuals killed are ambiguous, with press reports referring to "people killed" or "unknown" status, making it difficult to difficult to know whether to put those individuals in the numerator (civilian) or denominator (total). Indeed, this is one reason the government can claim zero civilian casualties but have that position be disputed by studies involving interviews of individuals on the ground near the attacks, where people might have a different understanding of the role the target had played in hostilities.
As this section suggests, the international legal questions surrounding the use of drones have hinged on both questions of sovereignty (jus ad bellum) and concerns about damage to civilians (jus in bello). With concerns in mind that its drone attacks had not been compatible with international law, the United States has, in recent years, gone to greater lengths to clarify its policies on the use of armed drones. In a talk at Northwestern School of Law, then-Attorney General Eric Holder outlined the legal basis for using lethal force in counterterrorism operations abroad, saying that the operations would be consistent with law of war principles.86 Holder spoke to the questions of sovereignty, arguing that "because the United States is in an armed conflict, we are authorized to take action against enemy belligerents under international law ... and international law recognizes the inherent right of national self-defense. None of this is changed by the fact that we are not in a conventional war." He thus outlined arguments both about being in a NIAC and also relating to selfdefense in terms of striking individuals outside places such as Afghanistan.
In a major speech a year later, President Obama continued the legal defense, arguing that strikes are conducted only against targets considered to be "a continuing and imminent threat to the American people," in areas "where there are no other governments capable of effectively addressing the threat" and where there is "near-certainty that no civilians will be killed or injured."87 This major speech gave the sense that the terms of counterterrorism operations had narrowed, and it does appear that there are fewer strikes than there had been during their peak in 2010. That the United States has felt compelled to respond to these legal concerns is indicative of the quite-vociferous opposition that the strikes had elicited. Nongovernmental organizations such as Amnesty International and international organizations such as the United Nations remain concerned that the United States targets individuals in ways that it deems extrajudicial or at least pushing the boundaries of international law.