Up to its dying days the self-declared Islamic State has retained the ability to top the news agenda, even as its fighters were losing their last battle for bomb-shattered villages in the deserts of eastern Syria. When their spokesman promised retaliation for the massacre of Muslims in the Christchurch mosques his threat was taken seriously.
Given the record of Isis atrocities it is not surprising that nobody can discount its ability to exact revenge through existing adherents, new converts or those using its name to spread terror. This is not just western paranoia: in Syria and Iraq people speak continually of Isis sleeper cells waiting to emerge and exact revenge.
There is a largely sterile debate about whether or not Isis – whose territory once stretched from the outskirts of Baghdad to the hills overlooking the Mediterranean – is dead and buried, as Donald Trump claims. Could it be reborn if the pressure against it is relaxed? The answer is simple enough: Isis is defeated as a state apparatus that once ruled eight million people, but it can persist as a terrorist and guerrilla organisation.
I was in Baghdad in June 2014 when Isis was advancing south towards the capital, capturing cities and towns like Tikrit and Baiji with scarcely a shot being fired. The rout of the Iraqi army seemed total and for several days there was no defensive lines between us and Isis advance patrols. As many as 1,700 Shia air force cadets were…