Within the Western just-war tradition, war is thought to be morally acceptable if it can satisfy certain ethical and procedural criteria. But that tradition also regards war as potentially causing so much suffering, death and destruction that leaders must carefully weigh those harms against the goals they hope to achieve through war. Even if one’s country has been seriously harmed, one’s citizens unjustly killed by foreign powers or terrorists, leaders still face significant moral constraints on what they may do in response.
 Most of us assume that we have a basic right not to be killed. We might not consider that an absolute right, but rather what philosophers call a prima facie right. For example, we might be said to forfeit that right if we commit a particularly heinous crime like aggravated murder. Or we might waive our right not to be killed if we suffer from a terminal illness and can’t end our own life without assistance from others. But we’re certainly on solid ground in believing that others would have to have very serious moral reasons to justify killing us.
 In war, soldiers are subject to being killed unless they surrender or are incapacitated by their wounds. The point is that combatants may justly be harmed only so long as they pose a credible threat to others. Most civilians pose no such threat, and thus may not be killed unless they choose to be in the vicinity of a legitimate military target. Moreover, if civilians are determined to be at risk in such an attack, then officials must carefully consider whether the target needs to be hit at all. If so, it should involve the least destructive force necessary to do the job.
 Those moral ideas are often encapsulated as rules of “noncombatant immunity” and “proportionality” in the just-war tradition. They have also been incorporated into international treaties to which the U.S. is a signatory-the Hague and Geneva conventions. Even if our enemies do not hold themselves to those standards, we cannot shirk our own responsibility to do so.
 William Shakespeare’s play about King Henry V of England, loosely based on historical events in the early 1400’s, provides a rich source of ethical issues in warfare and military leadership. It also provokes important questions about our current war in Afghanistan.
 Henry V was not only the direct heir to the English throne, but was also descended from a French king, and had other claims to parts of France through more distant ancestors as well as some recent treaties. At the beginning of Shakespeare’s play, Henry is deliberating with his close advisors about whether his claims on the French throne are strong enough to justify his going to war with France if they don’t yield. Henry asks the Archbishop of Canterbury for an assessment of his claims, and warns him to be scrupulously honest:
God forbid, my dear and faithful lord,
That you should fashion . . . or bow your reading. . . .
For God doth know how many now in health
Shall drop their blood in approbation
Of what your reverence shall incite us to.
Therefore take heed how you impawn our person,
How you awake our sleeping sword of war. . . .
For never two such kingdoms did contend
Without much fall of blood, whose guiltless drops
Are every one a woe, a sore complaint
‘Gainst him whose wrongs gives edge unto the swords
That makes such waste in brief mortality. (Act 1, scene 2)
 Henry indicates here that he is keenly aware of the high cost of war in innocent human lives, and therefore the moral importance of sincere and careful appraisal of the reasons offered in support of war. Unfortunately, Henry has surrounded himself with advisors who are all biased in favor of war. The Archbishop whom Henry trusts to provide an objective opinion actually has a hidden agenda, to fund Henry’s war in France in the hope of quashing a parliamentary bill that would have taken enormous tracts of church land. And Henry’s other advisors suggest that European monarchs will expect him to enforce his claims, like his ancestors did. They remind him of valiant Englishmen who died in previous wars with France, implying that their deaths will have been in vain if Henry allows it to slip from his grasp. And they appeal to his warlike courage and youthful desire to expand his power. None of them urges caution or careful consideration of French counter-claims. All of this has the effect of persuading Henry to go to war: “France being ours, we’ll bend it to our awe or break it all to pieces.” (1.2)
 He then receives a message from the French crown prince, who repudiates Henry’s claims and offers in their place a “treasure” of tennis balls, an insulting reference to Henry’s former reputation as a spoiled playboy. Even though it’s not clear that this message is sent with the knowledge or permission of the French king, Henry is deeply insulted by it, and says to the French ambassador:
Tell the pleasant Prince this mock of his
Hath turned his balls to gunstones, and his soul
Shall stand sore charged for the wasteful vengeance
That shall fly from them-for many a thousand widows
Shall this his mock mock out of their dear husbands,
Mock mothers from their sons, mock castles down. . . . (1.2)
 After Henry lands in France with his army, his relative Exeter delivers a similar ultimatum directly to the French king:
[King Henry bids you to] deliver up the crown, and to take mercy
On the poor souls for whom this hungry war
Opens his vasty jaws; and on your head
[Are laid] the widows’ tears, the orphans’ cries,
The dead men’s blood, the pining maidens’ groans,
For husbands, fathers, and betrothed lovers
That shall be swallowed in this controversy. (2.4)
 Notice that in contrast to Henry’s initial warning to his Archbishop, by this point he has completely shed any sense of personal responsibility for the destruction that the war will cause. All of its carnage will be the fault of the French. Now there’s obviously an important sense in which those who cause an unnecessary war are primarily responsible for the deaths that result. But it doesn’t follow that the other side is not also accountable for at least some of those deaths.
 I fear that we have repeated Henry’s mistake in our present war in Afghanistan.
 On the one hand, I think that the U.S. military deserves a lot of credit for the ways in which it has employed its weapons and tactics in Afghanistan, attacking only those targets that it believes to be directly connected with Al Qaeda and the Taliban, and using smart weapons to an unprecedented extent to limit civilian casualties. As Peter Steinfels pointed out in the New York Times on 6 April 2002, this represents a considerable improvement over our obliteration bombing of civilian areas in WWII and other conflicts.
 But many commentators have rightly criticized the U.S. Department of Defense for not assessing or reporting the number of Afghan civilians who have been killed or wounded by our weapons during the past year. Why has DoD failed to account for Afghan civilian casualties? According to the San Jose Mercury News, the DoD’s excuse is, “We were not trying to inflict civilian deaths; therefore, we are not counting civilian deaths.”
 An even more troubling reason why DoD personnel haven’t worried about those numbers in Afghanistan is that they don’t think they’re to blame for killing any civilians in this war. Secretary of Defense Donald Rumsfeld has frequently asserted that the responsibility for Afghan civilian deaths lies entirely with Al Qaeda and the Taliban.
 Now, it’s certainly fair to hold them primarily responsible for the current war in Afghanistan: Al Qaeda slaughtered over 3000 of our innocent civilians, and the Taliban not only refused to expel the terrorists from their country but actively supported and hid them. Neither organization has shown any respect for innocent people’s lives, Afghan or otherwise. And short of going to war, we could not realistically have punished Al Qaeda or seriously weakened its ability to wage massacres in the future.
 But when our bombs and missiles kill Afghan civilians, we share the responsibility for their deaths. We can’t shift all of the blame to Al Qaeda or the Taliban simply because they started this war. We must hold ourselves accountable as well. If we don’t, we risk sinking to their level of indiscriminate, total war.
 War is often hell, but it need not be. We’re morally obligated to do what we can to keep it from becoming hell. We must use weapons and tactics in ways that minimize civilian casualties, even as indirect consequences of legitimate military attacks. We can’t excuse our killing of civilians simply by claiming that we never intentionally targeted them.