When senior Israel Defense Forces officers are asked about the killing of hundreds of Palestinian civilians during the fighting in the Gaza Strip, they almost all give the same answer: The use of massive force was designed to protect the lives of the soldiers, and when faced with a choice between protecting the lives of Israeli soldiers and those of enemy civilians under whose protection the Hamas terrorists are operating, the soldiers take precedence.

The IDF's response to criticism does not sound improvised or argumentative. The army entered Gaza with the capacity to gauge with relatively high certainty the impact of fighting against terror in such a densely populated area. And it operated there not only with the backing of the legal opinion of the office of the Military Advocate General, but also on the basis of ethical theory, developed several years ago, that justifes its actions.

Prof. Asa Kasher of Tel Aviv University, an Israel Prize laureate in philosophy, is the philosopher who told the IDF that it was possible. In a recent interview with Haaretz Kasher said the army operated in accordance with a code of conduct developed about five years ago for fighting terrorism.

"The norms followed by the commanders in Gaza were generally appropriate," Kasher said. In Kasher's opinion there is no justification for endangering the lives of soldiers to avoid the killing of civilians who live in the vicinity of terrorists. According to Kasher, IDF Chief of Staff Gabi Ashkenazi "has been very familiar with our principles from the time the first document was drafted in 2003 to the present."

Kasher's argument is that in an area such as the Gaza Strip in which the IDF does not have effective control the overriding principle guiding the commanders is achieving their military objectives. Next in priority is protecting soldiers' lives, followed by avoiding injury to enemy civilians. In areas where Israel does have effective control, such as East Jerusalem, there is no justification for targeted killings in which civilians are also hit because Israel has the option of using routine policing procedures, such as arrests, that do not endanger innocent people.

Prof. Kasher has strong, long-standing ties with the army. He drafted the IDF ethical code of conduct in the mid-1990's. In 2003 he and Maj. Gen Amos Yadlin, now the head of Military Intelligence, published an article entitled "The Ethical Fight Against Terror." It justified the targeted assassination of terrorists, even at the price of hitting nearby Palestinian civilians. Subsequently Kasher, Yadlin, and a team that included IDF legal experts wrote a more comprehensive document on military ethics in fighting terror. Lt. Gen. Moshe Ya'alon, who was the IDF Chief of Staff at the time, did not make the document binding but Kasher says the ideas in the document were adopted in principle by Ya'alon and his successors. Kasher has presented them to IDF and Shin Bet security service personnel dozens of times.

"The article was translated into English and published in a military ethics journal and is still being debated around the world," Kasher said. "The feedback is generally positive, although the message is difficult to digest. In the end, everyone acknowledges that they conduct themselves this way. There is no army in the world that will endanger its soldiers in order to avoid hitting the neighbors of an enemy or terrorist. The media don't understand the nature of international law. It's not like tough traffic laws. Much of it is customary law. The decisive question is how enlightened countries conduct themselves. We in Israel are in a key position in the development of law in this field because we are on the front lines in the fight against terrorism. This is gradually being recognized both in the Israeli legal system and abroad. After the debate before the High Court of Justice on the issue of targeted killings there was no need to revise the document that Yadlin and I drafted even by one comma. What we are doing is becoming the law. These are concepts that are not purely legal, but also contain strong ethical elements.

"The Geneva Conventions are based on hundreds of years of tradition of the fair rules of combat. They were appropriate for classic warfare, where one army fought another. But in our time the whole business of rules of fair combat has been pushed aside. There are international efforts underway to revise the rules to accommodate the war against terrorism. According to the new provisions, there is still a distinction between who can and cannot be hit, but not in the blatant approach which existed in the past. The concept of proportionality has also changed. There is no logic in comparing the number of civilians and armed fighters killed on the Palestinian side, or comparing the number of Israelis killed by Qassam rockets to the number of Palestinians killed in Gaza."

When asked whether the IDF should be guided in its operations in Gaza by the concept that there should be zero tolerance for endangering the lives of soldiers, Kasher responds, "The soldiers' lives are endangered by virtue of their very presence in Gaza, by virtue of the fact that we send them to an area where there are enemy snipers and explosives set to go off in areas where the IDF is present. Sending a soldier there to fight terrorists is justified, but why should I force him to endanger himself much more than that so that the terrorist's neighbor isn't killed? I don't have an answer for that. From the standpoint of the state of Israel, the neighbor is much less important. I owe the soldier more. If it's between the soldier and the terrorist's neighbor, the priority is the soldier. Any country would do the same."

The decision regarding the magnitude of force used to protect the lives of the soldiers is up to the commander in the field. "The commander must be skilled in gauging the appropriate use of force," Kasher said.