The Palmachim Air Force Base is 15 kilometers (9 miles) south of Tel Aviv, tucked away in the dunes along the Mediterranean shore. A thin, bald man wearing rectangular, rimless glasses is standing in front of half a dozen combat helicopters on the airfield at the base.

He introduces himself as "Major I." A reservist in the Israeli armed forces, he ought to be looking after the restaurant he recently opened in downtown Tel Aviv. But since the end of December, his workplace has been the cockpit of a Cobra helicopter. "It's a crazy world," he says. "You're with your family in the morning and at war in Gaza in the afternoon."

Appropriately serious and yet relaxed, the 38-year-old major was probably selected by the Israeli army press office for the meeting with Spiegel because he comes across as being so intelligent and urbane.

Israel makes a distinction between terrorists and civilians -- that, at least, is the message the reservist keeps repeating in various forms. He shows an Israeli Air Force video that depicts Palestinian fighters taking cover behind a tree, firing off a rocket and then quickly driving away in a jeep. Black cross hairs can be seen following them. No other people are visible. Suddenly the jeep turns into the garage of an apartment building.

Then the cross hairs move away from the house and come to rest over an empty field. A bomb strikes the field a few seconds later. "We did everything possible in the war to protect the lives of innocent civilians," says Major I.

It is precisely statements like this that are being called into doubt, now that the Gaza campaign has come to an end. Each new image of destroyed residential buildings and every mother's complaint about the killing of her children puts Israel under growing pressure. Was the scale of the Israeli attacks justified? Did the Israelis take sufficient steps to protect the innocent? Were aid organizations prevented from evacuating civilians?

United Nations Secretary-General Ban Ki-moon, who visited the Gaza Strip last week, called for a "full investigation," Amnesty International is accusing Israel of "war crimes," and Louis Michel, the EU's commissioner for aid to developing countries, says: "It is evident that Israel does not respect international humanitarian law."

Officially, Israel vehemently denies such accusations, but its leadership is getting nervous. The office of the prosecutor general in Jerusalem is gearing up for a wave of lawsuits from around the world. The military is currently compiling a set of documentation for each complaint. Internal investigations have begun, and soldiers have been instructed not to comment on specific allegations.

It is a continuation of the war with legal means. The principal charge against Israel is that it reacted to shelling by Hamas fighters with disproportionate firepower, killing hundreds of civilians in the process. Some of the facilities the Israelis fired upon include a hospital, schools run by the United Nations and the U.N. headquarters building in Gaza City.

Palestinians across the board insist that Hamas would never have used these buildings as hiding places. But this argument crumbled last week, when it was revealed that Hamas had fired one of its rockets from the shelter of the Al-Shuruk tower in Gaza City, where many international television broadcasters had rented offices.

A recording that a correspondent for the Al-Arabiya Arab television network showed shortly before a live broadcast provides proof. In the tape, which was sent to the Israeli media, the sound of a rocket being fired can be heard, and the correspondent confirmed that "it was fired from below our office."

But even if Hamas fighters did fire rockets from the safety of mosques and schools, Israel's critics argue, bombing these buildings was excessive. The numbers speak more clearly than any accusation: 13 dead Israelis and 1,300 Palestinian casualties, including large numbers of civilians. Even if one takes the Israeli figure for Palestinian casualties -- about 700 dead -- the high death toll still raises a fundamental question: Can the laws of war even be applied to a conflict that has ended with such an overwhelmingly one-sided death toll?

Israel's huge military superiority, it seems, ran roughshod over not only the people of the Gaza Strip, but also the conventional laws of war. But is International Humanitarian Law (IHL), as it was essentially stipulated under the 1949 Geneva Conventions, even suited to protect the population in Gaza?

IHL, the benchmark for the treatment of war crimes, as well as the obligations of a country at war and its military, was developed for classic warfare between nations -- symmetrical shows of strength between two national armies that are essentially well-matched and clearly recognizable. But the conflict in the Gaza Strip was obviously asymmetrical. Israel's enemy is a group of terrorists that fights while in hiding and uses the civilian population as human shields. This alone is impermissible under the rules of the Geneva Conventions.

The asymmetrical wars of recent years, in the Middle East, in Africa or in Afghanistan, have led to the practice of the IHL rules being applied to such cases, albeit in modified form. If it is not possible -- be it from the air or the ground -- to identify exactly where the enemy is located and who is protected as a civilian under IHL, how can it be possible to strictly limit hostilities to combatants fighting for that enemy?

As brutal as it may sound, it would be unreasonable to expect a country to accept any legal restrictions that put it at a serious military disadvantage. A law of war that, within the framework of acceptable practices, requires the Israelis to exercise restraint on the level of force they use would not be enforceable. After all, an international law that is not accepted by individual countries is a law in name only.

In war, say most legal experts, each side must have the right to seek victory. Is Israel, for example, required to spare the bakery of a good citizen of Gaza who pulls out his bazooka from behind his oven at night to secretly take part in the fighting? It is not, because international law defines this citizen as an enemy. But how can this be verified? And who should make that decision before an attack?

Thus, the so-called principle of proportionality in war, even asymmetrical warfare, has only limited applicability. It does not cover the lives of enemies. In war, anyone can be killed who is considered part of the enemy, even if he bakes bread during the day. Although civilians who cannot be considered part of an enemy's forces cannot be targeted directly, many experts believe that that party's enemies can accept their deaths as "collateral damage" -- but only if the number of deaths is not blatantly disproportionate to the military value of the operation.

Part 2: No Fear of Conviction

The principle of proportionality in war sounds like an inhuman calculation performed by cynical opportunists. But war is war.

Or is it? Is it possible to ignore moral criteria altogether? When former U.S. President Bill Clinton had to decide whether to launch a particular rocket attack as part of the hunt for terrorist leader Osama bin Laden, he chose not to, because he had seen a children's swing on one of the reconnaissance photos. At the time, however, the United States was not officially at war with bin Laden. In a comparable situation, the human rights of the affected citizens must be respected -- and this is also the position taken by the Israeli Supreme Court in its rulings.

Israeli Prime Minister Ehud Olmert said Sunday that soldiers need not fear prosecution for war crimes abroad. "The commanders and soldiers that were sent on the task in Gaza should know that they are safe from any tribunal and that the state of Israel will assist them in this issue and protect them as they protected us with their bodies during the military operation in Gaza," he said.

The Israelis can argue that they have imposed strict restrictions on their army, especially for their asymmetrical war against terrorists. Asa Kascher of the University of Tel Aviv calls the charges of supposed war crimes "nonsense." Kascher, a philosophy professor, wrote the code of ethics for the Israeli armed forces and developed a set of central questions for the war against terrorism. Under his guidelines, Israeli officers are first required to determine:

• how immediate is the threat from a particular terrorist,
• how "involved" the suspect is, i.e., whether the suspect is a sympathizer, an informer or a combatant,
• how reliable the intelligence information about the location of terrorists is, and what weapons, ammunition and explosives are deemed appropriate for a mission.

Israel takes great pains to avoid civilian casualties, claims Kascher. But he also says that it is impossible to fight terrorism without collateral damage. "If I were to categorically rule out killing a terrorist if he is holding a child," says the philosopher, "I could no longer defend myself."

Off the record, however, Israeli soldiers admit that the units involved in Operation Cast Lead faced fewer restrictions than in past operations. This, they say, was mainly the result of lessons learned in the 2006 Lebanon war, where many Israeli soldiers died after being lured into ambushes.

Israel is also suspected of having used ammunition that causes particularly horrible injuries. The International Atomic Energy Authority (IAEA) is looking into charges that Israel used ammunition that contained depleted uranium. The Israeli army itself is already investigating a claim that 20 white phosphorus grenades were fired, in violation of military regulations, into residential areas in the northern Gaza Strip. Doctors in Gaza are also reporting previously unknown symptoms in some of their patients, including people who showed no visible damage but had severe internal injuries. Such injuries could have been caused by micro-shrapnel from so-called Dense Inert Metal Explosive (DIME) bombs.

Last week Israeli officers were instructed to consult with the office of Israel's chief public prosecutor before traveling abroad. Now that many countries, especially in Europe, have enacted their own national legal codes regarding war crimes, they could face arrest abroad.

That was what happened to Maj. Gen. Doron Almog in 2005. As the head of the Israeli military's Southern Command, Almog had signed off on various "targeted killings," including an operation on July 23, 2002, when 15 people died after a 1,000-kilo bomb was dropped over Gaza City. When Almog, now retired, flew to London, he discovered at the airport there that an arrest warrant for war crimes had been issued against him. The major general never left the aircraft, and returned to Israel without incident.

Translated from the German by Christopher Sultan