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Moral Theory and Drone Warfare: A Literature Review

Quinta Jurecic
Monday, August 17, 2015, 2:53 PM


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“Legal, ethical, and wise”: these are the three adjectives that the Obama administration has used again and again to describe its program of conducting targeted killings by drone strikes. John Brennan, then the White House’s counterterrorism advisor, used the phrase to justify the drone program in a speech at the Wilson Center in April 2012. Almost a year later, Press Secretary Jay Carney invoked the same phrase in defense of the leaked Department of Justice White Paper on the permissible targeted killing of a U.S. citizen and senior Al Qaeda in the Arabian Peninsula operative who posed an imminent threat.

Lawfare’s coverage of the drone program has focused largely on the phrase’s first and last terms: that is, whether the use of drone strikes in U.S. counterterror operations is legal (under both domestic and international law) and whether it is wise (that is, whether strikes are effective in practice). Less discussed on this site―though not overlooked―has been the question of whether drone strikes are ethical in theory and practice. By contrast, the public conversation on drones in no small part concerns questions of morality, not only on the side of those who criticize the use of drones for targeted killing, but also from within the administration itself. Both John Brennan and President Obama have extensively used the language of just war theory to defend the drone program to the public.

It’s significant, in other words, that the Obama administration has given the ethics of drone strikes equal billing to their legality and effectiveness. To understand the ongoing debate on drone strikes, it’s necessary to have some understanding not only of the legal and practical issues at the heart of the drone program, but of the moral issues as well. This is also true―perhaps even especially true―for those seeking to understand the debate from the perspective of the administration itself.

Consequently, I have put together the following literature review of the moral questions raised by U.S. drone strikes. It is not an exhaustive examination, but rather a brief overview of the relevant writing. It is divided into two parts, the first on questions raised specifically by the use of drones to conduct targeted killings, the second on questions raised by targeted killing more generally.


Moral Effects on Soldiers

Opponents of drone warfare often express concern over what they term as the “playstation mentality.” Because drone technology allows soldiers and CIA operatives to “kill by remote control,” as if playing a videogame, those same soldiers will lose some level of their courage or their sense of the moral seriousness of killing. In some sense, the argument goes, they will be no longer soldiers―or at least not soldiers in any sense that we now recognize.

Jonathan Glover’s book Humanity: A Moral History of the Twentieth Century reminds us that concerns over the moral disengagement of soldiers go back a long way. Examining the case of Royal Air Force bombing over German cities in World War II, Glover argues that the RAF pilots’ distance from their targets neutralized the “moral resources” that might have led them to feel sympathy for the civilians below. Robert Sparrow’s essay “War without Virtue” (which can be found in Killing by Remote Control: The Ethics of an Unmanned Military, edited by Bradley Jay Strawser) updates Glover’s concerns to the present day, questioning what effects the distant, mediated violence of drone warfare will have on the military virtue of mercy. His investigation also considers the interaction of drone warfare with other military virtues, including honor and loyalty.

One common argument posits that, given that drone pilots operate from the safety of the Nevada desert, drone warfare attenuates the military heroism and courage of soldiers. Christian Enemark’s Armed Drones and the Ethics of War and Gregoire Chamayou’s Theory of the Drone both provide paradigmatic statements of this position, arguing that targeted killing by drone allows a “post-heroic warfare” bereft of the possibilities for bravery and heroism that characterized past conflicts.

Popular literature on drone pilots has moved toward a focus on the psychological damage done to some pilots, who feel they have been morally compromised or otherwise harmed by their role in killing. (This GQ piece on former drone pilot Brandon Bryant has become a classic, largely as a consequence of Bryant’s harrowing description of his possible involvement in the death of a child.) Yet the critical literature doesn’t much address this question. It’s an interesting lacuna, and one that may be more explored as drones become further entrenched in our cultural consciousness.


Descriptions of “post-heroic warfare” are closely linked to arguments over the role of reciprocity in just war theory and drone warfare. Reciprocity, that is, refers to the reciprocal risk faced by soldiers in many (perhaps most) kinds of warfare, in which soldiers on both sides of the conflict are at risk of death or physical injury. Drone warfare is post-heroic warfare, the argument runs, because drone pilots are entirely safe from harm; they do not, unlike other soldiers, enter into a reciprocal relationship of risk with their enemies. Critics often argue that there is something dishonorable, cowardly, or even unjust about the safety of drone pilots.

It is best to begin with the NATO bombardment of Yugoslavia during the Kosovo War: NATO was roundly criticized for its decision to fly planes at high altitudes in order to protect its pilots from attack from below, at the cost of endangering civilians by decreased bombing accuracy. Paul Kahn’s essays on the subject (“War and Sacrifice in Kosovo” and “The Paradox of Riskless Warfare”) are a foundational statement of concern over an extreme lack of reciprocal risk. Kahn argues that the absence of reciprocity erodes the moral justification that allows soldiers to fight at all, for “combatants are allowed to injure each other just as long as they stand in a relationship of mutual risk.” (He adds, “It is no longer far-fetched to imagine military conflicts waged by small groups of high-tech warriors who select targets, push buttons, and are home for dinner”—though of course, by the time of the intervention in Kosovo, some U.S. soldiers were already fighting primarily by “selecting targets and pushing buttons” through use of long-range Tactical Tomahawk cruise missiles.)

Of course, this argument assumes that reciprocity is something morally required, or even desirable. But in the case of the U.S. drone program, is it? Answering this question requires us to examine what level of privileges and protections are due to those against whom the United States fights.

Michael Walzer’s foundational Just and Unjust Wars provides one paradigmatic view on the issue. Famously, Walzer argues for what he calls the “moral equality of soldiers”: in brief, we must treat soldiers as moral and legal equals no matter the justice or injustice of their cause according to just war theory. Soldiers fighting on both the just and unjust sides of wars, that is, have a right to fight, and could reasonably demand reciprocity in fighting. Walzer addresses this question most clearly in Chapter 3, “The Rules of War.”

Jeff McMahan has become well-known for his disagreement with Walzer on this matter, which he discusses in his essays “The Ethics of Killing in War” and “On the Moral Equality of Combatants.” In McMahan’s view, soldiers or combatants fighting for an unjust cause have no right to fight and commit a wrong in doing so. Kahn’s desire for reciprocity among combatants would be a fundamental non-sequitur as far as McMahan is concerned: if one soldier has the moral right to fight and the other does not, how can it be morally required that both soldiers are placed in the same danger? If we accept McMahan’s argument, then no reciprocity is merited in the current conflict if we believe our own cause just, and the drone program violates no such principle.

Reciprocity might also not be merited in the fight against ISIS, Al Qaeda, and similar forces because of those organizations’ essentially terroristic natures. Terrorists are often considered to have no right to fight, to be criminals rather than combatants because of their abhorrent tactics. Michael Gross’s Moral Dilemmas of Modern War considers the impact of asymmetric warfare and terrorist tactics on the moral equality of soldiers, particularly in Chapter 2, “Friends, Foes, or Brothers in Arms?”

Force Protection

To argue for reciprocal risk as a requirement for just conduct in war is, implicitly, to argue for the moral value of soldiers’ being placed in possibly mortal danger. Proponents of this idea don’t shy away from this implication: Michael Walzer asserts in an essay on Kosovo, in insistent italics, that “you can’t kill unless you are prepared to die.

(Walzer’s position is striking, but his reasoning is somewhat unclear: must we regard enemy soldiers’ lives as having equal moral weight as that of our own? Or is his insistence merely aimed at pushing us to regard the enemy’s lives as having some moral weight, perhaps not comparable to the lives of our own soldiers? And at what level of force protection does our continued combat become morally unacceptable?)

Walzer’s is obviously a proposition with some significant drawbacks, especially for the military commanders tasked with protecting those young recruits. And some scholars take the opposite view: that one is obliged to value the lives of one’s own soldiers over those of the enemy’s.

In his essay “Moral Predators: The Duty to Employ Uninhabited Aerial Vehicles,” Bradley Jay Strawser takes the position that the drone’s ability to protect soldiers from danger renders its use morally obligatory―as long as drone warfare is being used to carry out a just military action. (Uwe Steinhoff’s “Killing Them Safely: Extreme Asymmetry and its Discontents,” which is also available in Strawser’s Killing by Remote Control, offers a helpful critique of Strawser’s reasoning.) Kenneth Anderson (who is, of course, Lawfare’s book review editor) has on several occasions used the metaphor of “hostage-taking” to describe demands that soldiers’ lives be endangered. He has pointed out that the logical extension of taking seriously the moral necessity of subjecting your own soldiers to risk is to simply execute a few of them in the context of successful operations—a kind of sacrifice to the moral demand of risk.

Interestingly, there has been far less written on the moral value of drones’ ability to protect soldiers than on the moral difficulties presented by drone technology’s implicit rejection of reciprocity. It’s not clear why this should be the case, but the imbalance itself is worth noting.

Democratic Peace

In his 1795 essay “Perpetual Peace,” Immanuel Kant made the now-famous argument that democracies are less likely to go to war than authoritarian societies by the very nature of democracy itself. According to his reasoning, democracy’s ability to hold leaders accountable will render those leaders less bellicose: the people, who feel the costs of war in “blood and treasure,” will withdraw support from leaders who push them into war.

Democratic peace theory can therefore claim a pedigree stretching back well before the advent of the drone. Nevertheless, an important genus of objections to drone warfare is based on democratic peace theory. As the argument goes, drones have a perhaps unique ability to protect soldiers’ lives, and also are more cost-effective than other forms of military activity or technology. They therefore save both “blood and treasure” and thus shield the population from the consequences of war—thereby removing the protections against war identified by Kant two hundred years ago. There are many variations of this argument available, but John Kaag and Sarah Kreps’ volume on Drone Warfare provides a clear and paradigmatic statement. (Chapter 5 also contains a useful critique of Strawser’s argument in favor of the moral necessity of drones.)

Kaag and Kreps go further, arguing that drone warfare allows democracies to find a middle ground between politically unpopular war and politically popular peace: that is, prolonged warfare that does not substantially affect the lifestyle of the democratic populace. “Obviating popularly borne costs,” they write, “empowers democratic leaders to conduct affairs of state without public deliberation or support.” In other words, drone warfare may be cause concern in democracies.

Similarly, Frank Sauer and Niklas Schörnig’s essay “Killer Drones: The ‘Silver Bullet’ of Democratic Warfare?” takes the position that the low costs of drone warfare in “blood and treasure” make drones particularly attractive to democracies—hence the fact that democracies make up two-thirds of the countries that owned drones in 2012.


As our own Ben Wittes is fond of pointing out, many of the arguments made against drone strikes aren’t really arguments specific to the drone at all. They are platform-independent arguments about killing outside of warfare, about targeting individuals, about operating in the sovereign territories of unconsenting countries, and about civilian casualties. In this section, I zoom out a bit, examining moral questions that are not confined to targeted killing by drone but are instead relevant to targeted killing more broadly, particularly as used in asymmetric warfare.

Civilian Casualties

The question of civilian casualties is one of the most familiar and contentious issues surrounding the drone program. It is also, however, one of the most theoretically well-trodden.

The principle of distinction, as I have noted, is a foundational tenet of just war theory, particularly of jus in bello. Generally speaking, it states that soldiers may be attacked, but civilians should be immune; at least to the extent they are not participating directly in hostilities, they may not be the target of military attack. To put it another way, civilian deaths are to be avoided to as great an extent as possible, though where the limits of possibility lie is a matter of much debate.

The second foundational principle of jus in bello is that of proportionality: damage incurred from military attack must be confined to an extent proportional to the military advantage gained by the attack. In terms of civilian casualties, this limits the degree to which civilians are subject to violence during military action, not as the object of attack but as collateral damage.

Both of these principles are firmly established in contemporary International Humanitarian Law.

CIA Director Brennan and President Obama have both pointed to drones’ ability to distinguish between civilians and combatants, and their consequent honoring of the principle of proportionality, as among their chief virtues. The two have argued that drones’ surveillance capacity and loiter time allow drone pilots to “take the shot” only when certain that little or no collateral damage will result. In this way, they have placed the considerations of proportionality and distinction at the center of the debate on the morality of drone warfare as it is currently practiced.

Walzer’s Just and Unjust Wars puts forward a clear defense of the principle of distinction, which Walzer refers to as the “principle of noncombatant immunity.” To target a soldier for attack is permissible: a soldier, by the sheer fact of being a soldier, has been “made into a dangerous man.” But civilian life must be protected insofar as this is possible. Walzer examines a variety of cases in which civilian life was endangered for military advantage, concluding that civilians have a right that “due care” be taken to protect them—except in circumstances of “supreme emergency” when the enemy’s civilian population can permissibly be targeted in order to save the existence of a civilization. Walzer’s view is founded not only on just war theory but on an understanding of the human rights of civilians. Interested readers should look to Chapter 9 (“Noncombatant Immunity and Military Necessity”), Chapter 10 (“War Against Civilians”), Chapter 11 (“Guerrilla War”), and Chapter 16 (“Supreme Emergency”).

Traditionally, just war theory has considered cases of more or less symmetrical conflict. Michael Gross’s book Moral Dilemmas of Modern War considers how asymmetric warfare—which characterizes the U.S. targeted killing program—shapes the obligations of both sides to abide by noncombatant immunity. In Chapters 7 and 8 of his volume, Gross argues that while the principles of both distinction and proportionality should always remain in force, the proportionality must shift to accommodate the exigencies of asymmetric conflict.

Targeted Killings and Assassinations

There is also the question of assassination, a tactic against which there often exists an unspoken cultural prohibition. (A well-known U.S. executive order bans the practice, too.) Targeted killing by drone may remind us uncomfortably of this other kind of killing, in which an enemies are killed on an individualized basis outside of warfare—also an instance in which reciprocity is absent. Walzer (Just and Unjust Wars, Chapter 9, Section 1 on “The Status of Individuals”) studies how the intentional killing of a named, identifiable individual, such as by sniper fire, may strike us as particularly horrific. Gross (Chapter 5, “Murder, Self-Defense, or Execution?”) examines the distinctions between assassination and targeted killing in just warfare, and the justifiability of both. Gross’s earlier paper “Assassination: Killing in the Shadow of Self-Defense” is also helpful here.

Interested readers should look to Targeted Killings: Law and Morality in an Asymmetrical World, edited by Claire Finkelstein, Jens David Ohlin, and Andrew Altman—an exhaustive collection of essays on the moral as well as legal implications of targeted killing. Particularly relevant are Sections 3 (on the moral and legal justifiability of targeted killing as self-defense) and 5 (an exacting look at the moral reasoning and trade-offs involved in targeted killing).

Finally, Stephen de Wijze’s essay on “Targeted Killing: A ‘Dirty Hands’ Analysis” examines targeted killing through the lens of “dirty hands”: that is, a philosophical viewpoint that positions individuals as sometimes having to “do wrong to do right,” or, as de Wijze puts it, having to take an action that is “paradoxically both morally justified and morally reprehensible.” While the concept of dirty hands remains contentious within moral philosophy, de Wijze’s approach to targeted killings is a useful study of the thorny moral difficulties grappled with by political and military leaders.

Quinta Jurecic is a fellow in Governance Studies at the Brookings Institution and a senior editor at Lawfare. She previously served as Lawfare's managing editor and as an editorial writer for the Washington Post.

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