Islamic State is a hydra-headed military cult that grows two poisonous heads for every one lopped off. Yesterday's attacks in France, Tunisia, Kuwait and Somalia show IS-deployed or -inspired agents are popping up in many countries.
This weeks' offensives in Kobane, a Syrian town liberated by Kurdish fighters in January, and against Syrian government forces in Hassakeh demonstrate IS's dexterity and staying power. The two-pronged offensives followed IS routes from the Kurdish towns of Tel Abyad and Ain Issa, on the direct route from the Turkish border to the militant group's capital at Raqqa.
Killing civilians
Instead of responding with counter-attacks on Tel Abyad and Ain Issa, IS focused on Kobane and Hassakeh, surprising Kurdish fighters and Syrian troops, killing scores of civilians and driving tens of thousands from their homes.
Designed at least in part by battle-hardened veterans of the Iraqi army demobilised after the 2003 US occupation, IS strategy is based on several concepts.
The organisation selects targets giving it strategic dominance and access to economic assets providing independence.
Raqqa is a north central Syrian city 50km from the Turkish border across which most IS supplies and recruits travel. Raqqa is also a base from which IS can menace Aleppo to the west and oil rich Deir al-Zor to the east.
In Iraq IS holds Mosul, Ramadi and Fallujah, imposing control over the key Sunni majority provinces of Nineveh and Anbar. Both border on Syria, enabling IS fighters to deploy in both countries.
IS relies on surprise and terrorising opposing forces and local populations.
Although it had occupied parts of Ramadi and all Fallujah for six months, no one expected IS to conquer Mosul last June. It prepared carefully for this offensive by planting cells in Mosul. Sunni IS also relied on the majority of Sunni citizens, repressed by the Shia-fundamentalist regime in Baghdad, to accept IS rule.
Troops fled
Terrified by IS suicide bombings, decapitations, crucifixions and immolations, Iraqi troops fled, leaving vehicles and weapons behind. IS punishes civilian opponents too, blowing up and setting fire to homes.
IS reportedly has a constant stream of recruits, said to join at the rate of 1,000 a month. Foreign fighters are estimated to number 25,000. Few have been deterred by the US claim that its air strikes have killed 10,000. IS recruits are largely dedicated volunteers rather than the conscripts used in the regular Syrian and Iraqi armies and the men pressed to join pro-government militias.
In Raqqa and elsewhere, IS has moved into areas captured by al-Qaeda affiliate Jabhat al-Nusra and other insurgent factions and expelled them. It executes fighters from rival groups, more than two dozen this week. IS mounts an impressive and effective outreach campaign to win recruits and supporters by making effective use of social media and YouTube.
Thousands of messages are sent daily via Twitter by operatives and sympathisers who broadcast the message that Raqqa and Mosul are twin capitals in the 21st century utopian Islamic caliphate proclaimed last year. This message appeals to many alienated Muslims across the world.
IS counts on the support of Turkey, Saudi Arabia, Qatar, the ineffectiveness of US air strikes and the absence of a coherent western policy.
Although this week’s IS convoys carrying fighters to Palmyra and Ramadi should have been spotted by drones and satellites, the US did not mount airstrikes to take out the jihadis.