Once again the fat is in the fire. Hamas called off a shaky, 6-month-old cease-fire with Israel, and Israel responded with a massive air attack on Gaza that is still under way at week's end. Israel claimed the right of self-defense, saying it could no longer tolerate constant rocket attacks along its southern frontier. Hamas claimed Israel had virtually imprisoned 1.5 million Palestinians in the narrow Gaza Strip since the Israeli withdrawal in 2005, leaving Hamas little choice in defending its people.

Once again, each side has engaged in a pathological defense of its position: Hamas, that only violence would end Israeli occupation of Palestinian land; Israel, that only violence could put an end to Hamas' terrorist activities.

Both are wrong.

Hamas cannot destroy Israel, but then neither can Israel destroy Hamas. Israel will continue to win all the battles but will never win the war. It cannot win because military victory is impossible. Only a political settlement can bring a solution.

The world cannot — and does not — deny Israel the right of self-defense. But there is the vital question of proportionality. There is no doubt that the homemade rockets Hamas fires into southern Israel have made life miserable for the people of that area, especially in the city of Sderot. The rockets cannot be guided, and while they are generally ineffective, they are deadly if one happens to fall on you. Since the Israeli withdrawal from Gaza in 2005, about three Israelis have been killed from rocket fire. That is three too many.

But in just a few days of Israeli air attacks, some 400 Palestinians were killed, many of them women and children. That is unacceptable and amounts to collective punishment. The Israelis, of all people, should find collective punishment not only deeply offensive, but a crime.

If the Hamas rockets have made life miserable for the people of Sderot, the Israeli blockade of the past three years has made life intolerable for the Palestinians. The economy has collapsed. Everything, including vital medical supplies, is in short supply. Israel's opening of the border posts for a few hours to allow in supplies will not change the situation. It is grim and getting grimmer.

In military terms, Israel is one of the most powerful countries in the world. Hamas has its armed wing, and that wing indulges in terrorist activities. But in military terms, the Palestinian territories and the Palestinian people are defenseless. What's wrong with this picture? Something has to change.

One of the complicating factors is the political division among the Palestinians. Hamas is not just a semimilitary organization that resorts to acts of terror, it is also a civilian organization that in 2007 seized control of Gaza from Fatah, the dominant political faction headed by Palestinian President Mahmoud Abbas. Hamas had already won an open election in Gaza, astounding the Bush administration. Hamas won largely because it was perceived by Gazans to be more honest and competent than Fatah. It was — that's why they won.

The Palestinian Authority and Israel enjoy mutual recognition, though Israel has done little to bolster Abbas' position. Hamas is bent on the destruction of Israel — a futile cause — and the world in general regards Hamas as a terrorist organization, regardless of its civilian activities. The Arab world as a whole does not trust Hamas, which is why Egypt and Jordan have done little to help in the current crisis.

While Abbas, as well as the Egyptian, Jordanian and Saudi leaders, condemn the Israeli attacks — what else can they do? — they also hope that Hamas is severely damaged by the Israelis. Abbas hopes to gain with the military destruction of Hamas, perhaps even restoring Gaza to the control of the Palestinian Authority. Certainly the Egyptians won't complain, nor will the Jordanians and the U.S. It would make life a lot easier for everyone.

But that is the midterm prospect. The immediate prospect is the further destruction of the Gaza Strip by the overwhelming might of the Israeli Self Defense Force. Israel itself is scheduled for elections early this year, and Defense Minister Ehud Barak, the former prime minister, will enhance his chances for an even more prominent role if the attack on Gaza is successful.

Israel invaded Lebanon a few years ago in what is widely regarded not only as a disastrous political mistake but also a bungled military operation. Hezbollah, which the Israelis sought to destroy, emerged stronger then ever in Lebanon. The Israeli military would like to avoid making that same mistake in Gaza, and so a successful operation would restore not only the military's reputation but enhance that of Barak and the ruling Kadima Party. If not, the chances are that Benjamin Netanyahu, the man who did more than any individual to destroy the Oslo Accords and the right-wing Likud Party, will win. That would be in nobody's interests other than the Likud rejectionists.

A great deal is at stake here, and not just for Gaza and the people of Gaza. The world is rapidly changing before our eyes and those of Barack Obama, soon to be our president.

William M. Stewart, a former U.S. Foreign Service officer and Time magazine correspondent, lives in Santa Fe. He writes weekly on foreign affairs and politics.