This is not surprising. IS patterns its military strategy on that of the Prophet Muhammad, which is to say it organises ghazwa (raids) against soft targets. The Muslim warrior has always been known as the ghazi, a man who takes part in a ghazwa. However, a ghazwa is regarded as religiously permissible only if the ghazis are more than 50 per cent sure of victory. Otherwise, they should return and wait for a better day. That is what the Prophet himself did in his only attempt at ghazwa against the Byzantines.

Waging at least one annual ghazwa became an almost religious obligation for Islamic caliphs and rulers from the eighth century onwards. And for a long while the ghazis enjoyed a number of advantages. They could decide the time and place for launching their raids as well as which target to choose, thus always retaining the initiative. Their enemies, the Persians still fighting in the uplands and the Byzantines resisting in Anatolia, were forced merely to react, often long after the event.

It took the Persians and the Byzantines almost two centuries to learn the trick. They understood that, facing no resistance, the ghazi moves rapidly ahead, like a knife through butter, but would come to a halt if he encounters something hard on his way. In Persia the Buyid tribes of the uplands bordering the Caspian Sea decided to use the tactic against the Arabs, by becoming counter-ghazis. The ghazwa knife was blunted and several Iranian provinces along the Caspian Sea never fell to “holy warriors”. The Byzantine Emperor Basil I (867-886) also learned the trick and, organising his own ghazwas, stopped the Arab advance in Anatolia. It was not until 1071 that the ghazis, this time Turks not Arabs, managed to defeat the Byzantines at the second Battle of Manzikert.

Continuing the tradition, IS goes where it is easy to go and flees from where it is difficult to resist. Last year its forces moved into Palmyra because nobody tried to stop them. Next, they tried to enter Suwaida in south-west Syria and amassed a large number of fighters and weapons for the ghazwa. The city had the advantage of being home to the Druze minority, providing IS with a tempting target. (Islamists regard the Druze as heretics who must be slaughtered.)

IS carried out two probing attacks on two Druze villages in Al-Huqf close to the Jordanian border in May and June 2015, decapitating five “miscreants”. Druze fighters then came in from Suwaida and engaged IS in a battle, killing 11 of them. IS quietly withdrew.

IS understood that the Druze would not quietly go to slaughter as the peace-loving Yazidis in Iraq had done. As Druze fighters from everywhere, including Lebanon and Jordan, poured into Suwaida for the showdown, IS realised that the cost-benefit of the projected ghazwa was not worth the effort. The caravan of ghazis had to make a U-turn back to Palmyra and Raqqa.