Beyond securing the adoration of his own people, Arafat also began to make many powerful friends abroad. The East German leader Erich Honecker regarded him as a true revolutionary, like Fidel Castro, and his spies provided Palestinians with intelligence and weapons. At the same time, the C.I.A. had cultivated Arafat through a back channel, an effort with support at the highest levels. As the 1970s drew to a close, Arafat seemed untouchable. He was a de facto head of state with broad support. Openly assassinating such a man would break all of the norms of international relations. The Israelis looked on and ground their teeth.

By 1979, Israel and the P.L.O. had settled into a rote and seemingly endless pattern of strikes and counterstrikes. And then a horrifying murder raised the tension even higher. On April 22, 1979, a terror squad from the Palestine Liberation Front, a P.L.O.-affiliated group, landed in a rubber dinghy on the beach at Nahariya, an Israeli city six miles south of the Lebanese border. One of its four members was Samir Kuntar, then 16 years old. After trying to break into a house and being frightened away by gunfire, and after killing a policeman who tried to arrest them, the men broke into a family’s apartment and took Danny Haran, and his daughter Einat, 4, as hostages. They dragged them to the beach, where soldiers and police had already deployed, and a firefight ensued. Kuntar shot Danny, killing him, and then smashed Einat’s head with the butt of his rifle until she was dead. Danny’s wife, Smadar, hid in a crawl space in their apartment with their 2-year-old daughter, Yael. Smadar covered the toddler’s mouth with her hand, to keep her from crying out and allowing the attackers to find them. In her panic, she smothered her child.

In the wake of the Nahariya atrocity, Raful Eitan, the I.D.F. general, gave the regional commander Avigdor Ben-Gal a simple order: “Kill them all,” meaning all members of the P.L.O. and anyone connected to the organization in Lebanon. With Eitan’s blessing, Ben-Gal appointed the man he considered the I.D.F.’s top expert in special ops, Meir Dagan, to lead the efforts in south Lebanon. The three of them set up the Front for the Liberation of Lebanon From Foreigners. The operation ran almost entirely without the authorization or knowledge of the rest of the military, the defense ministry, the intelligence agencies or the government. (I did not speak with Eitan, who died in 2004, about any of these events.)

Between 1979 and early 1983, when it disbanded, the Front killed hundreds of people. David Agmon was head of the I.D.F.’s Northern Command staff, one of the few who knew of Dagan’s secret ops. “The aim,” he said, “was to cause chaos among the Palestinians and Syrians in Lebanon, without leaving an Israeli fingerprint, to give them the feeling that they were constantly under attack and to instill them with a sense of insecurity.” In order to do that, Dagan and his crew recruited Lebanese locals: Druze, Christians and Shiite Muslims who resented the Palestinians and wanted them out of Lebanon.

On Aug. 5, 1981, Prime Minister Menachem Begin appointed Ariel Sharon as defense minister of Israel. Begin, a hero of the underground movement in Israel’s prestate era, had a deep admiration for the former general — “a glorious commander of armies,” he called him — but he was somewhat apprehensive about Sharon’s unwillingness to accept the authority of his superiors. “Sharon is liable to attack the Knesset with tanks,” one of Begin’s deputies half-joked two years earlier.

Sharon quickly raised the stakes. He put a renewed focus on Arafat and gave the greenlight for Ben-Gal and Dagan to carry out an operation that, if it succeeded, would change the course of Middle East history. Operation Olympia called for Israeli agents to plant a massive set of bombs under a V.I.P. dais under construction in a Beirut stadium where, on Jan. 1, 1982, the P.L.O. was going to celebrate the anniversary of its first operation against Israel. With the push of one button, they would achieve the destruction of the entire Palestinian leadership.

Everything was ready, including powerful explosive charges already secreted beneath the dais, as well as three vehicles loaded with explosives that were supposed to be parked on the streets around the stadium; these were to detonate about a minute after the dais exploded, when the panic was at its height and the survivors of the initial blast were trying to flee the scene. The resulting death and destruction were expected to be “of unprecedented proportions, even in terms of Lebanon,” in the words of a very senior officer of the Northern Command. But a group of worried AMAN officers, as well as the deputy defense minister, went to Begin and demanded that he order Dagan to call it off. “You can’t just kill a whole stadium,” one officer recalled telling Begin. “The whole world will be after us.” Begin shut down the operation.