In 2014, a new state was formed in the heart of the Middle East. It had a capital, a government, an army and almost 12 million subjects — a larger population than Jordan or Israel. It also had a commitment to butchery, savagery and fanatical violence that quickly earned it the enmity of the entire civilised world.

That universal enmity made it hard to imagine how this state of many names — the Islamic State, ISIS, Daesh — could long survive. At the time, I offered a speculative analogy to the Bolsheviks in Russia, another ruthless bunch of revolutionary terrorists who faced general opprobrium and foreign interventions but survived to govern Russia for several generations.