Asymmetric warfare involves, by definition, conflict between weaker and stronger antagonists—strength here as denominated in the quantity of material resources and the quality of technological sophistication that can be brought to bear against the enemy. The strong—the United States, preeminently—are tempted to deploy overwhelming force against opponents who lack the capacity to respond in kind, and so use whatever inexpensive and vicious technologies lie at hand: IEDs, hijacked airplanes, truck bombs, suicide bombers, explosives smuggled into nightclubs, and so on. The cycle of violence is joined and stretches downward without an end in sight.
 In asymmetric warfare, both sides try to reduce their vulnerability to each other’s attacks. While the weak may disclaim vulnerability altogether by celebrating their dead as martyrs, the strong seek to immunize their combatants against harm. One striking feature of the asymmetric war declared by the U.S. on terror is ‘radical force protection’ –the strategy of reducing to zero the casualties suffered by American combatants. Protecting one’s forces is hardly new; the idea of substituting weapons platforms that are distant from the battlefield for boots on the ground has been in the ascendant for at least a century. Think of the contrast between the exposed trench warfare of World War I and the high-altitude bombing of World War II and the drones of today. This trend was visible to me in Vietnam, where I learned of how the American side countered the hit-and-run tactics of the Vietcong. Typically, the Vietcong made their presence known in a village. The U.S. and South Vietnamese forces called in artillery fire and aerial bombardments to pulverize the village, and only then would send in ground forces.
Drone Now the trend has reached its ultimate expression: the self-described ‘radical’ aspiration of conducting warfare without risk to personnel, as when warfare is conducted by drones piloted from half a world away or by stealth bombers high beyond the reach of any antiaircraft fire or missiles. Two acronyms are needed here. I here will lump these technologies under the term ‘invulnerable weapons platforms’ (IWPs). IWPs afford their pilots what I will call ‘combatant immunity’ (CI). CI a novel twist in war-fighting, made possible by warfare that is technologically asymmetric. CI merits ethical appraisal because it moves the vulnerability of combatants from being an unavoidable feature of fighting to being a matter of choice—certainly for pilots, and perhaps someday for grunts.
 CI, or the radical invulnerability of combatants to enemy harm, raises at least two sets of moral questions. First, is it morally problematic for the stronger parties in asymmetric warfare to kill the enemy without that enemy having a chance to respond? In effect, are IWPs a just means to prosecute a war? This first round of questions invites the kind of dry, distanced analysis familiar to just-war theory, which I will pursue before turning to a second set of issues more familiar to Lutheran theology: is it morally permissible for the stronger party in asymmetric warfare to harm the consciences of its own invulnerable combatants by subjecting them to the moral injury which results when they participate in such one-sided killing?
Just War Theory Does Not Address Combatant Immunity
 To simplify the first set of issues, I will ignore the question of whether IWPs are in compliance with international law and turn instead to just-war theory as a device for moral reflection. Here I stand within the ELCA magisterium, inasmuch as its social statement For Peace in God’s World seeks “guidance from the principles of the ‘just/unjust war’ tradition”.1
Alas, however, the principles which encapsulate the wisdom of this tradition offer little help with the question of combatant immunity. IWPs may meet the just-war criteria of both discrimination and proportionality, in that they might produce much lower rates of civilian harm than would ground forces used to accomplish the same objectives. However, just war theory limits the scope of such utilitarian thinking to benefit for noncombatants. Consider, for example, Michael Walzer’s Just and Unjust Wars. He begins his discussion of war crimes with the claim that “the war convention2 requires soldiers to accept personal risks rather than kill innocent people” (305). Note that it is the prospect of harm to noncombatants, not enemy combatants, that provides reasons why soldiers may not immunize themselves against harm. His reasoning is characteristic of the just-war tradition, in that the in bello principle of discrimination classically addresses only the protection of civilians, not the relative vulnerability of combatants on the strong and weak sides in asymmetric warfare. So the question remains: is there any reason grounded in justice why combatants should not seek to put themselves beyond reach of harm from their enemies?3
 Of course, drone ‘pilots’ and pilots of high-altitude bombers cannot put themselves beyond the reach of all harm. They may suffer remorse, or even a disability now recognized as “moral injury”. According to the Department of Veteran Affairs, “moral injury” is caused by events which “transgress deeply held moral beliefs and expectations”.4 These wounds are inflicted not by the enemy directly, but by the sensitive consciences of the pilots themselves, consciences that are abraded and lacerated over time by the long-distance killing they are causing. It is not hard to see why “moral injury” might happen. Raining fire on a weaker foe from IWPs may not engage the principles of discrimination or proportionality, but it certainly might generate moral unease. From the lofty and privileged perspective of a drone, war-fighting smacks more of extermination than combat. The ‘pilot’ hovers over the target, enjoying a mobile frame of view that is frankly (obscenely?) godlike in its panoptic view from horizon to horizon—and in its access to destructive power. With a flick of the joystick, the ‘pilot’ kills the enemy, who has no chance to fight back5 or to surrender.6 The timing of the fatal shot is known only to the ‘pilot’, while the insurgent below is deprived of any awareness that the moment of his death has arrived. Without a foxhole, there is no opportunity for the atheist to find God, let alone be a warrior by defending himself against his attacker.7
 What are we saying about our enemies and ourselves when we render ourselves utterly beyond their reach? Especially for pilots entering the sheltering cocoon of an IWP, we might ask: is physical vulnerability simply an evil to be purged from their lives? Or is there some value for combatants to be vulnerable in some significant way to attack by their enemies? The very idea may seem bizarre from the vantage point of military prudence. And for a culture which invests heavily in the reduction of vulnerability—from airbags to insurance policies to pre-nuptial agreements to gated communities—it may seem morally perverse to ask soldiers to consent to any more vulnerability than what technology can protect them against, whether in the form of Kevlar jockstraps or lumbering MRAPs (mine resistant ambush protected vehicles) in Iraq. I, for one, would not toss aside any available body protection if dropped into Swat Valley in Pakistan. Yet there is a morally significant difference between protecting myself against an enemy who is in a position to shoot at me, and making it physically impossible for him to reach me while I proceed to destroy him at my leisure.
Martin Luther on Vulnerability as a Human Condition
 At issue, quite bluntly, is how much—if any—vulnerability a soldier should be subjected to. The potential for drones and other weapons platforms to generate “moral injury” opens up familiar territory for Lutheran ethics, perhaps more familiar than the cool, distanced rationalism of just-war theory. After all, Martin Luther addressed his one extended tract on soldiering specifically to a knight who feared the worst kind of vulnerability—that his participation in combat was putting the salvation of his immortal soul at risk. Vulnerability is a rich term for reflection in Lutheran ethics. For the balance of this essay, then, I will develop some ideas that are evident or latent in Luther’s thinking regarding the ambiguous potential of combatant immunity.
 Most generally, for Luther, vulnerability to natural and social forces was a ubiquitous feature of the creaturely condition. In his early (1520) The Freedom of a Christian, he distinguished the true Christian’s invulnerability of the spirit (“…nothing is able to do him harm…”) from the “physical power” enjoyed by kings and princes. “We know from our daily life that our experience is like that of other people—we suffer many things and even die. Indeed, the more Christian a person is the more evil, suffering and death he must endure…” (66). For Luther, earthly vulnerability is not simply an unavoidable negative, where we might regret not having leverage over our circumstances. Vulnerability has positive value, in driving Christians to repose their trust in God, and for schooling Christians to live humbly in God’s creation. In his commentary on the Sermon on the Mount some ten years later, Luther more than once asks his readers to consent to their vulnerability. He counsels husbands to put up with the messiness of marriage (21:95), victims of legal “rogues and rascals” to “suffer injustice innocently” (21:114), defendants to yield to their victimization in court (21:115-6), and Christians generally “to willingly and patiently suffer whatever is [their] lot, without seeking revenge or hitting back” (21:107).
 Perhaps the most striking endorsement of earthly vulnerability appears in Luther’s 1524 treatise On Trade and Usury. Luther first denounces the efforts of merchants to curb their risk in exposure to the marketplace. Drawing upon Matthew 5, Luther asserts there are three religiously commendable ways to exchange goods: let them be stolen, give them away freely, lend without expectation of return. These three ways involve “not presuming upon the future and not trusting in any man or in oneself but clinging to God alone” (45:255-257). For Luther, a true Christian takes Jesus’ injunctions in the Sermon on the Mount literally as marching orders. True Christians are characterized by their willingness to consent to any degree of vulnerability in their total reliance on God. But he quickly acknowledges such Christians are rare, and so he quickly returns to standard buying and selling. With no little distaste, he proceeds to review the ingenious ways that merchants immunize themselves against risk and take advantage of the vulnerability of others. Ultimately he throws up his hands in disgust; clearly, a “strict, harsh temporal government” is needed to suppress the “theft and robbery” practiced by merchants (45:258, 258-273). Yet his concession to economic ‘risk management’ is not total; threaded through his discussion is the conviction that economic actors should entrust themselves to God rather than seek to immunize themselves against risk.
 Luther’s endorsement of earthly vulnerability is striking by modern standards but still not absolute. When life itself is at stake, he refrains from suggesting that Christians ought simply to consent to any vulnerability that presents itself. Consider his advice in Whether One May Flee from a Deadly Plague (1527). At issue is who has divine permission to flee plague-ridden towns to places of relative safety in the countryside. Luther insists that those with particular civic and religious offices must remain in their towns, out of an obligation to help the sick (43:120-1). These responsible individuals are to hew a middle way between recklessness, which tempts God, and timidity, which fails to serve the neighbor. While this middle way involves taking on vulnerability, it does not mandate what one might term ‘doormat vulnerability’. Even though God sent the plague to punish Germany, in Luther’s view, the Germans who are being punished nevertheless should use medicines to protect themselves. Luther also commends the prophylactic measure of quarantining victims. His ethic of service to neighbor does not require lethal self-sacrifice.
 In sum, Luther offers a rich account of human vulnerability, one which offers cold comfort to those who seek to immunize themselves against the many and various ways that their well-being and even their lives can be put at risk. The problem with such immunizations appears at root theological: to the extent that we protect ourselves against risk, we are failing to trust God’s governance of the world—and of our own eternal fates. As such, his thinking might plausibly be interpreted as presenting skeptical resistance to the idea of complete invulnerability as is being pursued by military planners today. Keenly alert to the idols we erect instead of depending upon God, Luther might even term ambitious strategies like ‘radical force protection’ as idolatrous.
 Note my use of the conditional ‘might’. In his (1536) Whether Soldiers, Too, Can Be Saved Luther does not follow the pattern of endorsing vulnerability.8 Rather, his thinking takes a pastoral turn, for he is addressing the burdened conscience of Assa von Kram and other soldiers who fear damnation because their profession requires them to violate Jesus’ command not to kill. The concern of Assa von Kram and other soldiers is actually not too far from modern pilots who send forth destruction from IWPs and suffer “moral injury” as a result. To soldiers in such spiritual peril, Luther’s primary word is one of reassurance: he counsels them to acknowledge, in prayer, that they are saved only by God’s Word and Christ’s blood; they should be confident that their work is aligned with God’s will (46:135). But here is where the problem starts, for modern pilots: how can they be sure that exercising invulnerable, godlike power over the lives of their enemies is what God indeed wants?
Towards a Confidence that Transcends Vulnerability and Anxiety
 Luther displays no awareness of how innovation in military technology might serve to reduce the vulnerability of military personnel. Such technical developments still lay far in the future. Yet he makes one striking claim at the end of Whether Soldiers, Too, Can Be Saved that points us in the direction of an answer. He boasts that soldiers who are humbly aware of their dependence upon God alone will prove to be “invincible” fighters. Their “invincibility” comes not from the conviction that their cause is just, or that their prince is brilliant, or that their armor is impenetrable. It comes from trusting that God wants them to carry out the “external” work of soldiering, combined with the firm knowledge that their salvation in no way depends on how well they carry out this good work (46:136). In sum, Luther is suggesting that the vulnerability of soldiers to God’s own judgment is wondrously transmuted, when they are confident in their own justification, into invincible warrior power. This invincibility need not imply invulnerability. The point is that soldiers who have a solid conviction of their justification will fight wholeheartedly, without concern for their own physical vulnerability, since that vulnerability concerns only their earthly existence, and they are not subject to the final harm of damnation afterwards.
 Such disregard of earthly survival might be pushed in the direction of suicidal martyrdom except for the fact that Luther inscribes it firmly within the nature of the soldier’s vocation—which, as he makes very clear early in Whether Soldiers, Too, Can Be Saved is to preserve saving the social “body” (46:96-97). These soldiers will be “invincible” because they become instruments focused on preserving the good order of society. They will perform their duties in a way that is undistracted by anxieties concerning their own salvation and so will be more effective soldiers. They will not be carried away either by vanity into recklessness, or by despair into nihilistic destruction. In a word, they will fight not as egos seeking acclaim or reward, but as willing instruments fully harmonized with God’s will to preserve creation. This disinterested instrumentality is echoed in Luther’s advice to princes, that they stick to their duties to protect their people and avoid wars of vanity (46:121-124). The earthly benefit of justification is capacity to focus disinterestedly on preserving creation.
 What does such creation-centered invincibility tell us regarding the challenge of ‘combatant immunity’? Luther devotes much of Whether Soldiers, Too, Can Be Saved to the ad bellum conditions under which a mercenary soldier may fight in good conscience, and so we can extrapolate his thinking to see how he might have handled the challenge of combatant immunity. Early in the tract, he draws a sharp distinction between the office of soldiering and the person who carries it out, and proceeds to argue that war-fighting is not sullied if the person who carries it out is corrupt (46:94, 97). At the end of the tract, as we have just seen, his boast about invincible soldiers addresses the opposite situation: soldiers and princes who are without anxiety about their own salvation and therefore are fully available to the roles they need to carry out in preserving creation. At issue, then, is what the office of soldier, uncorrupted in its disinterested instrumentality, says about the assignment to exterminate soldiers from invulnerable weapons platforms.
 Unfortunately, Luther offers no explicit advice in Whether Soldiers, Too, Can Be Saved concerning whether soldiers are to exterminate their enemy combatants, but elsewhere he addresses the matter in a tantalizing if incomplete way. In his commentary on the Sermon on the Mount, Luther engages in a lengthy and tortuous commentary on Matthew 5:43-48. According to Luther, Jesus commanded loving our enemies. This love is not indulgent; it does not override the office-based duty “to punish and to resist evil” (21:123). Christians are to carry out the tasks mandated by their offices, tasks which presumably include the duty of killing when one is a soldier. But then Luther, following Matthew closely, takes a turn in his thinking that opens up a startling new perspective: he refuses to dismiss enemies as unworthy of God’s love (21:125-129). He warmly endorses Jesus’ claim that God sends sun and rain to sustain the lives of even the most wicked enemies who want to destroy His kingdom on earth; after all, even the worst of those wicked souls practice love and friendship among themselves. Luther never declares explicitly that God loves these enemies of Creation, but he is clear about how Christians are to respond: we are to follow the “sublime example” of God in manifesting a love which treats all alike and excludes no one. We are to accept continuing vulnerability by helping and not harming those who hate us (21:128-129). In short, Luther affirms both the office of state-sponsored killing and the value of the enemy that is greater than what the office implies.
 Such a view of the enemy implicitly calls into question the immunity that invulnerable weapons platforms confer upon combatants. A conscientious pilot might well ask: can I be confident I am carrying out my duty to Creation when I am exterminating my enemy from a privileged sanctuary? Luther might have replied: the value of my enemy for God is not exhausted by his enmity towards me or even my homeland. Even my enemy is my neighbor, in some sense. After all, God is willing to subject Creation to the continuing spate of insults and rebellions of wicked people who try to destroy it. If God forbears punishment out of love, so perhaps should I also follow Jesus in acknowledging the value of my enemy? And if so, can I in good conscience engage in the pitiless extermination of my enemy, rather than meet him—in some meaningful sense—in combat?
 Unfortunately the trail runs cold just at this crucial stage of the argument. If Luther had extended Jesus’ generous view of enemies to apply to soldiers in their office of soldiering, he would provide us firm grounds for rethinking combatant immunity. Alternatively, if he intended Jesus’ command to apply only to Christians as private persons, then there might be no gospel limit on killing from an invulnerable weapons platform. Luther does not pursue the argument far enough to indicate where the line should be drawn between neighbor and enemy. Yet there is latent moral grandeur in his account of knights and soldiers who are liberated by justification to focus exclusively upon their offices, which includes treating enemies as God would. Detached from concerns about personal salvation and well-being, they are free to focus upon how a war really should be fought, and what limits are to be observed in the killing of enemies.
 Overall, this exploration yields few definitive clues for a Lutheran assessment of invulnerable weapons platforms and combatant immunity in asymmetric warfare. In the first part, I argue that just-war theory does not provide a determinative answer, in no small measure because its in bello criteria address the vulnerability of noncombatants, not of combatants, and because invulnerable weapons platforms offer the utilitarian good of fewer casualties than traditional ground-based fighting. When turning to Luther’s own thought, I sketch the endorsement of vulnerability that runs through his social ethics, but again without a determinative answer. Luther commends vulnerability as both inevitable and valuable in the human condition but offers no explicit indication of how much is appropriate in the work of a soldier. Still, he opens up two breathtaking if undeveloped moral vistas. He first sketches the bold confidence that combatants might bring to their task, thereby suggesting they might adopt a disinterested attitude towards the protection of Creation. Second, he commends a generous love of enemy, even to the point of taking on vulnerability; such a love might find the prospect of exterminating enemies to be contrary to God’s will. These two claims tend to cast a moral shadow over the use of IWPs, but in all truth, they remain as undeveloped implications in Luther’s thought.
 Not surprisingly, more work is needed. The emergence of combatant immunity as a technological achievement suggests that Lutheran ethics might take a deeper look at the aspirational professional ethic that U.S. soldiers are encouraged to adhere to. With its frank endorsement of professional roles as masks of God, and its equally frank acknowledgement that earthly life does and ought to entail vulnerability, Lutheran ethics might be very well placed to serve as a tool of conscience for rethinking the ethic of the warrior, as well as for assessing emerging strategies and tactics in the U.S. military.
1. For Peace in God’s World, a social statement adopted by the ELCA in 1995, section 4B.
2. The “war convention” is his term for the “articulated norms, customs, professional codes, legal precepts, religious and philosophical principles, and reciprocal arrangements that shape our judgments of military conduct”(44).
3. In Walzer’s view, soldiers are in a position of “moral equality” with one another—enjoying an equal right to kill each other; he asserts that such quality is what makes war morally tolerable (36-41). If he were aware of the possibility that the technologically stronger side might immunize itself against harm from the weaker side, I wonder whether he might argue that combatant immunity violates this fundamental equality.
4. Shira Maguen and Brett Litz, “Moral Injury in the Context of War”, U.S. Department of Veterans Affairs. http://www.ptsd.va.gov/professional/pages/moral_injury_at_war.asp accessed 25 May 2012, citing Litz, B.T., Stein, N., Delaney, E., Lebowitz, L., Nash, W.P., Silva, C., & Maguen, S. (2009). “Moral injury and moral repair in war veterans: A preliminary model and intervention strategy,” Clinical Psychology Review, 29, 695-706.
5. Targets on the ground as seen from drones bear a resemblance to Walzer’s “naked soldier”—a person who, being exposed in an uncovered state, evokes moral sentiment of sympathy for that vulnerability (142-143).
6. If a soldier has the right to surrender—to disengage from hostilities, there might here be an opening wedge for an argument against combatant immunity. See Walzer’s discussion of surrender on 46, 177.
7. This concern may not be widely shared. According to a recent New York Times article, many drone operators find the work stressful, but mostly because of long hours and frequent shift changes. Fewer than 4% were showing signs of PTSD, and ‘moral injury’ was not reported as a cause of stress http://www.nytimes.com/2011/12/19/world/asia/air-force-drone-operators-show-high-levels-of-stress.html, accessed on 24 May, 2012.
8. At one point he makes his usual refrain about how fragile are human lives—how subject to misfortune (46:117)–but interestingly enough, he does not focus on the vulnerability of the soldier per se.