TEL AVIV, Israel—Since news of the killing of longtime Hezbollah leader Hassan Nasrallah began spreading across the Middle East, spontaneous celebrations broke out in places like the rebel-held city of Idlib, Syria—locales where the terror group had fought and built its reputation for ruthlessness.

The severity of Israel’s attacks have called into question the very reason for the organization's existence, which was predicated on deterring Israeli attacks against Lebanon and Iran.

J ust when the prospect of peace in the Middle East seemed further away than ever, the dramatic death of longtime Hezbollah leader Hassan Nasrallah significantly alters the balance of power and offers a renewed opportunity for peace.