The death of Hassan Nasrallah, who led Hezbollah for more than three decades, will be a political earthquake for the movement.

Hassan Nasrallah, the iconic leader of Hezbollah who captivated many in the Arab world with his charismatic oratory, was killed on Friday in an Israeli attack on Beirut. At the apex of his career, the cleric was so popular that shops sold DVDs of his speeches, and many Lebanese used lines from them as ringtones. But he was also loathed or feared by rivals for the formidable power he wielded, both politically and militarily, well beyond Lebanon’s borders. Nasrallah’s death will be a political earthquake for Hezbollah, a Shiite movement that he built from clandestine terrorist cells thirty-two years ago into a powerful political party, network of social services, and the most heavily armed non-state militia in the world today. It could have a rippling impact across the volatile Middle East, with implications for the United States, too. The Biden Administration, which had already sent more troops in response to increasing violence between Israel and Hezbollah, moved quickly to assess the safety of U.S. military personnel and diplomats in the region.

The bombings, which killed other top Hezbollah officials, and civilians, in the Lebanese capital, “crossed the threshold of all-out war” and sought “to deliver a mortal blow,” Firas Maksad, a Lebanese American who is a senior fellow at the Middle East Institute, in Washington, told me. Hezbollah is “reeling” from the wave of Israeli military and intelligence operations conducted in the past two weeks, he added. Its military wing has been decapitated in the targeted assassinations of top commanders. Israel has also carried out extensive air strikes on what it has said were weapons caches and other military infrastructure, and has also been blamed for sabotage of pagers and walkie-talkies used by Hezbollah fighters and followers that injured thousands.

Nasrallah, who often invoked both God and guns with a distinctive lisp, wore a black turban signifying his descent from the Prophet Muhammad. He had dreamt from an early age about leading Lebanon’s Shiites, he told me, in 2006. “When I was ten or eleven, my grandmother had a scarf,” Nasrallah said. “It was black, but a long one. I used to wrap it around my head.” Then he would tell his family, “I’m a cleric, you need to pray behind me.” He mobilized allies well beyond Lebanon. After the U.S. assassinated Qassem Soleimani, the Iranian general and regional strategist, in 2020, Nasrallah became even more pivotal to the so-called Axis of Resistance under Iran’s tutelage.

Hezbollah emerged to fight Israel during its second invasion of Lebanon, in 1982, when Nasrallah was just twenty-two years old. “We noticed what happened in Palestine, in the West Bank, in the Gaza Strip, in the Golan, in the Sinai,” Nasrallah told me. “We reached a conclusion that we cannot rely on the Arab League states, nor on the United Nations.” He went on, “The only way that we have is to take up arms and fight the occupation forces.”

Nasrallah’s death will weaken but not eliminate the movement—or the threat it poses to Israel. The C.I.A estimated earlier this year that Hezbollah had up to fifty thousand armed combatants, full- or part-time. Many have battlefield experience from fighting in Syria’s civil war. (Hezbollah sought to bolster the regime of the Syrian President, Bashar al-Assad, one of Iran’s most important Arab allies.) And it still has a vast arsenal of missiles and rockets. Hezbollah is an “exponentially more capable military organization” than it was when Israel killed Nasrallah’s predecessor, Abbas al-Musawi, in 1992, Maksad said. It is possible that Hezbollah’s militia may soon respond by fighting “as if this war had no limit, no ceiling and no redlines.”

The audacious attack, during which more than eighty bombs were dropped on residential buildings that sit atop the group’s underground headquarters, was ordered by Prime Minister Benjamin Netanyahu from New York, before delivering a speech at the United Nations General Assembly. Hezbollah, he said, angrily, is a “quintessential terror organization” with tentacles worldwide. “It’s murdered the citizens of many countries represented in this room,” he said. He described Hezbollah’s cross-border attacks into Israel, which it undertook in solidarity with Hamas during the year-long war in Gaza, as “intolerable.” More than sixty thousand Israelis have fled northern Israel as a result, emptying out entire towns. “I’ve come here today to say enough is enough,” he told the assembly. Shortly thereafter, the bombs were unleashed. Israel rarely acknowledges its military operations, but this time the Prime Minister’s office released a picture of Netanyahu on the phone communicating the order.

The Israeli operation made a mockery of U.S. diplomacy. Just two days earlier, the Biden Administration—alongside allies in the Middle East, Europe, and Asia—had announced a plan for a twenty-one-day ceasefire between Hezbollah and Israel. In a late-night briefing on Wednesday, a senior U.S. official claimed that they had worked “tirelessly” with Israel and Lebanon on the terms. (The Lebanese government has often acted as an interlocutor with Hezbollah, which holds cabinet posts and parliamentary seats in Lebanon but is designated as a terrorist organization by the United States.) Just hours before the Israeli strike, John Kirby, the strategic coördinator for the National Security Council, confirmed that the U.S. believed it had buy-in from Israel. Netanyahu stiffed U.S. diplomats—again. In May, President Biden rolled out a three-phase ceasefire plan for Gaza that his Administration said was based on Israeli demands and was supported by Netanyahu. It has gone nowhere in four months.

The Secretary of Defense, Lloyd Austin, claimed that the U.S. did not know about the attack on Nasrallah until after it started. (Iran’s Foreign Minister, Abbas Araghchi, told the U.N. Security Council on Friday that Washington was complicit because Israel had used five-thousand-pound bombs, known as “bunker busters,” acquired from the U.S.) The Israel Defense Forces issued a statement that the operation was carried out “while the top brass of Hezbollah were at their headquarters and engaged in coordinating terror activities against the citizens of the State of Israel.” Israel had, for years, considered going after Nasrallah, who took over Hezbollah in 1992 and oversaw some of the suicide bombings and rocket attacks on Israeli forces during their eighteen-year occupation of southern Lebanon, which ended in 2000. Nasrallah lost his eldest son, Hadi, during a firefight with Israeli forces; his nickname became Abu Hadi, or “father of Hadi.” Hezbollah ultimately forced Israel to withdraw—the first time it had done so from any Arab land without a peace treaty.

In 2006, Daniel Ayalon, Israel’s Ambassador to the U.S., called Nasrallah “the shrewdest leader in the Arab world—and the most dangerous” during the second full-scale confrontation between the two parties, after Hezbollah’s cross-border raid killed and captured Israeli soldiers. That war ended in a stalemate after thirty-four days of fighting that destroyed swaths of the Dahiya, the Beirut suburb where Hezbollah is headquartered. Hezbollah claimed a victory because it ceded no territory or political concessions. For the next eighteen years, Israel opted not to go after Nasrallah because of the potential consequences. Israeli intelligence and military officials have in the past told me that they considered Nasrallah, who trained as a cleric in Iraq and Iran, to be a relatively rational actor, even though he was beholden to Iran for funding and an increasingly sophisticated arsenal.

The death of Nasrallah allows Israel to claim a short-term tactical success. Yet, as in the war in Gaza, Israel has not defined a long-term strategy. It has provided no sense of an endgame or what it seeks after the Hezbollah campaign is over, Dan Kurtzer, the former U.S. Ambassador to Israel and Egypt, told me. “They don’t have a metric by which to measure when they’ve accomplished enough,” Kurtzer said.

Israel’s operations in Gaza and Lebanon recall past wars in both places—and both times Israel voluntarily opted to withdraw after its own death toll became politically and militarily intolerable. Now it’s returned to both places. And Lebanon, about one-third the size of Maryland, is far bigger than Gaza, which is about the size of greater Philadelphia. The notion that Israel can do anything to guarantee that either group will never attack it again is unrealistic, Kurtzer said. “At some point, though, they’ve got to look in the mirror and say, you know, ‘Somebody’s going to have to impose a ceasefire on us, because we don’t know, we can’t define when to stop.’ ”

Zohar Palti, the former chief of Mossad’s intelligence directorate, told me that Israel was not responsible for what happens next in Lebanon. “The Lebanese have to decide,” he said. “And I think that right now, since yesterday, we gave them a golden slot in order to regather themselves and to build something from the ashes.” Lebanon’s Army will have to try to wrest power from, and replace, Hezbollah. “Let’s see if they have the ability to do it,” Palti said. “And, if not, we will understand that Lebanon is not a state anymore, and we’ll have to, I don’t know, recalculate what we’re doing.” But the Lebanese state has been barely functional for decades and is still ruled by the same politicians that fought a civil war against one another between 1975 and 1990; it has also suffered from a devastating economic crisis. Hezbollah became so powerful in part because the state was so weak, and riven by sectarian divisions.

Nasrallah’s death has also stunned Iran, Hezbollah’s lifelong strategic partner. Shortly after the Israeli bombings, Iran’s Supreme Leader, Ayatollah Ali Khamenei, summoned the Supreme National Security Council to his home for an emergency meeting. Since April, Israeli operations have assassinated two Revolutionary Guard generals visiting Syria; a senior Hamas commander in Lebanon; the political chief of Hamas visiting Tehran for the inauguration of Iran’s new President; and now the Hezbollah chief. “All the resistance forces in the region stand with and support Hezbollah,” Khamenei said, in a statement on Saturday. At the same time, Iran heightened security at home—and reportedly moved Khamenei to a more secure location.

In a statement on Saturday, President Biden said the Israeli assassination of Nasrallah was “a measure of justice for his many victims, including thousands of Americans, Israelis, and Lebanese civilians.” He emphasized the Hezbollah leader’s “fateful decision” to join hands with Hamas and open a northern front against Israel. The U.S. goal now, he added, is to de-escalate both conflicts in Gaza and Lebanon through the two diplomatic proposals. “It is time for these deals to close, for the threats to Israel to be removed, and for the broader Middle East region to gain greater stability.” The odds of either seem small right now. ♦