By assassinating Hizbollah leader Hassan Nasrallah, Israel has dealt a grievous blow to one of its most powerful foes. Over three decades, Nasrallah transformed the group, with Iranian backing, into the Middle East’s most heavily armed non-state actor and the dominant political force in Lebanon. His killing has severely wounded the movement, while underlining Israel’s military superiority over Iran’s so-called axis of resistance.

Many other senior Hizbollah figures have been killed in Israeli air strikes. But the relentless bombardment has wrought devastation on Lebanon, spreading fear and panic across the nation. More than 1,000 people have been killed in the past two weeks, and up to 1mn forced from their homes. As the bombs rain down, they fear what comes next. Many in Lebanon opposed Nasrallah and blamed Hizbollah for the crisis-ridden country’s ills. But Hizbollah also represents a large swath of Shia society in a fragile nation where Muslim and Christian sects coexist uneasily. Under Nasrallah, the movement was cohesive and disciplined. In his absence, many worry it might fragment or become more extreme.

Israelis, too, should be wary. They celebrated the death of their foe, but having a failed state on their northern border, or a more extremist enemy bent on revenge, will not serve their security interests. Hizbollah has been battered, but it will not disappear. History has shown that when one militant leader is killed, another steps into the breach, often more radical than the former.