Yet the idea of organisational decapitation remains seductive to would-be strategic assassins: cut off the leader and watch the body twitch through its death throes. In a book published last November, Jenna Jordan of the Georgia Institute of Technology examines more than 1,000 cases involving the killing or capture of leaders of terrorist or insurgent groups. She says three factors contribute to a group’s resilience afterwards: its degree of bureaucracy, ability to draw on local resources and ideological zeal. These qualities ensure that its mission does not depend on a single leader.

The death last October of Baghdadi, the self-proclaimed caliph of Islamic State, who blew up himself (and two of his children) to avoid capture by American forces in Syria, has disrupted IS, but perhaps not in a lasting manner. IS ranks highly on all three of Ms Jordan’s factors. It has kept meticulous records and exported its procedures to international franchises that can apply them independently. Though it no longer pulls in $1m a day, as it once did, it still has deep pockets, and is likely to benefit from local Sunni disaffection in Syria. Its ideological purity resonates independently of Baghdadi, to whom a successor was named within days. It has proved its resilience before. It is notable that Mr Baghdadi rose to the top because two predecessors were killed in American strikes in 2006 and 2010.

General Suleimani will no doubt be hard to replace. He was the right-hand man to the supreme leader, Ali Khamenei, and no obvious candidate can take that role. But like Baghdadi, he had created something much bigger than himself that does not depend on him alone.