At 5:20 on the morning of March 22, Sheik Ahmed Yassin, the spiritual leader of Palestinian Hamas, was leaving a mosque in the Gaza Strip when he was killed in an Israeli helicopter gunship attack–a “targeted” assassination that left nine others dead and caused several serious injuries. A half-blind quadriplegic in his late 60s, Yassin was in his wheelchair when he died; his body will be added to the trail of thousands of Palestinian and Arab corpses that Israeli Prime Minister Ariel Sharon (who is reported to have personally supervised the Gaza hit) has piled up since the 1950s, when he conducted brutal raids against Arab villagers across Israel’s border. The attack–condemned by the entire world apart from the United States–is yet another reminder of Sharon’s disregard not only of Arab life but of the lives of his fellow Israelis, many of whom are likely to perish in the “earthquake” of revenge Hamas has promised in retaliation.

Sheik Yassin, to be sure, was not a man of peace. His group has killed hundreds of Israeli civilians in suicide attacks since the mid-1990s. But Yassin, along with Ismail Abu Shanab, who was assassinated last year, represented the more moderate current within Hamas; although Yassin refused to recognize the legitimacy of the Jewish state, he had spoken favorably of a “hundred-year truce” with it and had indicated that violent resistance would cease once Israel withdrew to its 1967 borders. Now that Yassin is dead, the only men left standing are the hard-liners, led by Dr. Abdel Aziz al-Rantisi, the sheik’s successor in Gaza. Some “friends” of Israel–a curious term for those who cheer Israel on as it marches down the road to self-destruction–will doubtless observe that Yassin would not himself have flinched from a comparable attack on Israelis. But that is precisely the point. Under Sharon’s leadership, Israel is increasingly behaving like a rogue state, heedless of international legal norms and contemptuous of civilian life. With its indiscriminate raids, the government has chosen the path of escalation, putting its own citizens in jeopardy.

The Yassin assassination, a turning point in a conflict that grows uglier by the day, appears to be a calculated and deeply cynical move by Sharon, “the champion of violent solutions,” in the words of Israeli historian Avi Shlaim. Contrary to official claims, the intention is not to fight terror but to exploit it politically. The Yassin killing comes on the heels of Sharon’s February 2 announcement that he intends to withdraw Israeli troops from Gaza in one to two years and to evacuate Gaza’s 7,500 Jewish settlers. Sharon’s deepest fear is that the Gaza withdrawal will be perceived as a victory for Hamas and Islamic Jihad, much as Ehud Barak’s withdrawal from southern Lebanon in May 2000 was hailed as a triumph for the Shiite guerrilla organization Hezbollah. To avert such an outcome, Sharon appears determined to decapitate Hamas’s leadership–Israel has vowed to carry out more such attacks–and to make Gaza bleed. The recent twin suicide bombings by Hamas and the Al-Aqsa Martyrs Brigades in the Israeli port city of Ashdod, in which ten Israelis were killed–which followed the killing of twenty-six Palestinians in Gaza over two weeks of Israeli incursions–was the perfect pretext to launch the army’s offensive. There may be another reason as well: The day after Yassin’s assassination, Oded Granot, the chief Arab affairs correspondent for Israel’s government-owned Channel 1 News, reported that Hamas and Yasir Arafat’s Fatah had been on the verge of signing a cooperation agreement that would have led to joint control of Gaza’s security apparatus in the wake of an Israeli pullout. The Israelis feared that if this were to occur, Washington would call a halt to the assassination of Hamas leaders. So the killing of Yassin may have been designed as much to pre-empt these developments as to avenge the Ashdod bombing.

If Yassin’s assassination triggers an earthquake of revenge, Sharon is willing to pay the price–indeed, it might even shore up his popularity among Israel’s battered, frightened citizens. A wave of suicide attacks would bolster Sharon’s efforts to frame the conflict as a war against Islamic terrorists rather than one between occupier and occupied–and to continue with the project most dear to him, the colonization of the West Bank (where he wants to transfer the Gaza settlers) and the creation of a 400-mile wall that carves up Palestinian land into an archipelago of prisonlike cantons, divided from one another and cut off from their natural resources.

There may be another casualty of the assassination: the remarkable flowering of nonviolent resistance to Israel’s wall. Over the past six weeks Palestinians, led by older veterans from the first intifada, and Israeli activists have joined in protests in villages near the wall, facing ferocious assaults from the Israeli army–an attempt, it would seem, to transform nonviolent resistance into rioting and to discourage wider participation. From Sharon’s vantage point, nothing could be more menacing than the emergence of a nonviolent movement of civil disobedience, particularly one in which Jews and Arabs work together.

Yassin’s killing can only reinforce the intercommunal, religious dimension of the Israeli-Palestinian conflict, with repercussions that are profoundly alarming not only for Israelis and Palestinians but for those beyond the region. As veteran Israeli peace activist Uri Avnery put it, “This is the beginning of a new chapter…. It moves the conflict from the level of solvable national conflict to the level of religious conflict, which by its very nature is insoluble.” Yassin was a revered cleric throughout the Muslim world, and his death has enraged millions not only against Israel but against Washington, its indispensable patron; in Iraq, the pre-eminent Shiite leader Ayatollah Ali al-Sistani condemned the assassination as “an ugly crime against the Palestinian people” and protesters in Mosul chanted, “Do not worry, Palestine. Iraq will avenge the assassination of Sheik Yassin.” Hamas has indicated for the first time that it also holds America directly responsible for the killing of its leaders. It is also worth recalling that when Israel killed Hezbollah leader Sheik Abbas Musawi in a similar helicopter gunship attack, revenge came not in Israel but in Argentina, where Shiite militants bombed the Israeli Embassy, killing twenty-nine. The US government must not merely urge “restraint”–its timorous response to Yassin’s killing–but prevent its Israeli ally from leading the region into catastrophe.