The mission statement of the Israel Defense Forces announces that the Army operates:   To defend the existence, territorial integrity and sovereignty of the state of Israel. To protect the inhabitants of Israel and to combat all forms of terrorism which threaten daily life. - IDF Doctrine: Ethics   This statement seems to offer an ethically adequate position in relation to a classical war situation: defense and protection of the state and its residents by sending armed forces to the battlefield, where conventional rules of warfare apply.   The war against terrorism, however, is played out under different conditions. As the Israeli-Palestinian conflict unfolded, the IDF came to realize that finer ethical distinctions were required if it were to remain committed to an adequate war ethics.     The IDF ethical code was composed in order to meet the need for clear guidelines for operational activity that invariably takes place within densely populated areas. Naturally, these guidelines can only serve as broad pointers for the soldiers engaged in combat.   I make a distinction between two categories of war ethics. One category relates to the justifications for entering war, and the other pertains to the conduct within a war situation. Certain theories and practices consider these two categories to be identical, to the extent that if the other party is responsible for opening the war, it is also accountable for any atrocity that takes place during the war. This position therefore legitimates unethical warfare by an army with justified reasons for entering war. The IDF ethical code, however, is based on the conviction that these categories are separate and independent from one another.   In light of the above we must ask two questions: what are the justified conditions for engaging in war, and what are the ways to fight justly in war. The question regarding the justifiable conditions for opening in war is mainly political, as long as we assume that war is a legitimate act of self defense, and that self defense includes also preemptive measures. Granted that, I will stay away from the political to focus on the ethical, and examine the second category of just warfare in light of two guiding principles: proportionality and restriction.   Principle of proportionality   The principle of proportionality justifies the use of force by army personnel only in proportion to the mission s/he is assigned. This principle already appears in the Talmud, which permits the use of force against an assailant in self-defense. This category, known as din rodeph, restricts the use of force with the following reservation:   If one can save oneself from assault by limiting the damage to injury then one is not allowed to kill one's assailant in self-defense.   The principle of proportionality functions precisely according to the same considerations.   Hence, when ordering soldiers to search a house, breaking the house door is necessary for carrying out the mission; breaking the TV found inside the house isn't. Breaking the TV exceeds the proportions of the mission and is therefore unjustified and wrong. The strategic and tactical importance of the mission definition is quite obvious. Any officer will tell you that a mission poorly defined is doomed to fail.   To this I add the moral significance of mission planning, because the use of force ought to be proportionate to the mission itself. Reading the first line of the ethical code's section "purity of arms":   The soldier shall make use of his weapon and force solely for executing his mission, only to the extent required.     Observing this principle in combat is no simple matter. Returning to the house from the previous example, once he destroyed the other party's capacity to threaten him, the soldier must refrain from using firepower. The use of force is proportionate to the mission defined. But how many times in combat can we know with absolute certainty when our enemy ceases to be a threat?   The discernment of combat conditions and matching them with the mission goal is one challenge. It is preceded, however, by a more fundamental question: how can we discern the moral criteria for defining the mission? What exactly is the mission when we blockade a city? We could say that it is aimed to stop terrorists from leaving the city and entering Israel Proper.   Alternately, we could aim to unsettle the life fabric of the general population, in order to cause it to pressure its political elite to make political or military compromises.   It therefore emerges that discernment is one of the biggest challenges the principle of proportionality poses: discernment of the conditions within the combat situation and of the mission definition itself. To that we must add a third and final obstacle.   Infantry troops are trained to fight upholding "the drive for engagement": the requirement to engage with the enemy whenever possible. However, in the unique conditions of anti-terrorism warfare, the application of this rule may become highly complex. Many times soldiers are hard-pressed to differentiate enemy targets from innocent civilians. The unfortunate outcome of off-beam targeting is familiar to all of us from the news.     In seeking to observe the principle of proportionality, the IDF had defined initially the military conflict with the Palestinians as a low-intensity conflict. This means that military forces need employ greater discretion in the use of their firepower than in conventional, high-intensity, combat situations.   But this definition contradicts the drive for engagement. The result is that an infantry brigade deployed in a Palestinian city is expected to keep its operational activity at low intensity, when it is trained to maximize the intensity of any hostile engagement. Therefore, we find that the operation of a conventional army against targets embedded in civilian population leads to an asymmetrical conflict.   Restrictive principle   Now we come to the second category of war ethics, that of restriction, which supersedes proportionality in importance. The restrictive principle forbids the targeting of non-combatants even when it is proportionate with the completion of the mission. This principle is reflected in the IDF's ethical code as follows:   IDF soldiers will not use their weapons and force to harm human beings who are not combatants or prisoners of war.   One may only kill those who enter the game of combat. Those who do not partake of the wargame cannot be included in your mission. It is therefore clear that the restrictive principle overrides the principle of proportionality.   On the face of it, there couldn't be a clearer moral requirement. Everything changes, however, when the other party intentionally blurs the distinction between combatants and non-combatants by operating from within its civilian population.   Admittedly, there are radical cases in which it is morally permitted to make an exception to the restrictive principle: when your civilian population or your sovereignty is threatened. If Iran, for example, were to attack Israel with missiles armed with chemical or biological warheads, many would justify a nuclear counterattack, even though it is likely to hurt combatants and non-combatants indiscriminately.   At this juncture we must ask ourselves whether an asymmetrical conflict can also impose an existential threat on a civilian population to point that it warrants breaching the restrictive principle.   The Iranian example is relatively straightforward, but what about terror attacks? Is the threshold 12 dead victims a day? 20 victims a day? People's fear to travel on buses? How can we identify the condition permitting us to lift the restriction on our use of force against a hostile party?   We'll come back to the radical examples. But in an ordinary course of asymmetrical warfare there is the further challenge of deaths of non-combatants who are not targeted, what the Americans call collateral damage, appearing in the ethical code as follows:   [Soldiers] will do all in their power to avoid causing harm to their lives, bodies, dignity and property.   The authors of the document are fully aware that there will be situations in which civilians will get hurt. But such situations should not arise out of premeditated targeting of non-combatants. An IDF order to "kill this old man," or "kill this small boy," to deter their terrorist family members is an illegal order, because it specifically targets a non-combatant.   In seeking to overcome ethically the problem of collateral damage, one could opt for one of two easy solutions: refuse to engage in conflict or use force indiscriminately. I believe that these solutions are too easy, and that we must embark on the challenging middle road.     Ethical conduct of war requires from us to refrain from targeting civilians, all the more within an asymmetrical conflict. Therefore, targeting a combatant, while risking the lives of non-combatants when your own soldiers or civilians are not under an immediate threat, is ethically prohibited.   For instance, we may not target a terrorist who is driving a taxi with innocent non-combatants, even granting that killing him is justified. One might say we are targeting the terrorist, and that we do not bear any responsibility toward the others traveling with him. If the terrorist is not posing a clear and present danger and there is a good chance for capturing him at a later opportunity, we may not act as long as we are risking the lives of non-combatants. As far as I know, this is how the IDF operates in these scenarios.   The so-called targeted killings of terrorists are performed with great care to avoid collateral damage when civilians are likely to be hurt as a result. The heter (license) for inflicting collateral damage exists when soldiers or civilians are under an immediate threat from a combatant embedded in a non-combatant environment.   The distinction between an immediate threat and a non-immediate threat is not plainly evident. Such a situation exposes the limitations of an ethical code and underscores the importance of discretion and judgment in real time. These are essential tools for discerning right action from wrong when operating within the unique and challenging conditions in which the IDF operates.   IDF and challenge of applicability   As far as I'm aware, based on the army's ethical code, officers and soldiers are expected to act according to both principles of proportionality and restriction. These expectations, however, take into account the two inherent difficulties of discerning the objectives of military missions and differentiating between combatants and non-combatants.   These are challenges of micro-morality, by which I mean that the actual moral choices are not made by the high command but by the troops in the battlefield. This scenario is vastly different from World War II, for instance, where Allied forces sent squadrons to bomb Dresden, or Harry Truman sent bombers to Hiroshima and Nagasaki. These were macro-conflicts that entailed massive mobilization of forces in which the moral agents were the heads of the army.   In the Israeli-Palestinian conflict every soldier is a moral agent, because of its nature as a micro-conflict. We cannot be content with the knowledge that army generals possess the ethical sensibilities expressed in the code; we must provide the necessary education to the soldier who is sent to face the enemy.   The section on "the purity of arms" in the IDF ethical code integrates proportionality and restriction into the army's operational policy. This is our attempt at maintaining a certain sense of moral integrity in the way we handle the conflict militarily. It also requires from us to reject two easier, and in my view, immoral positions of one of two extremes: minimizing operational activities for fear of harming innocents, or directing force indiscriminately at military targets embedded in the civilian population.   Adapted by Orr Scharf from a lecture.