It has been proved in Algeria, Egypt, Libya, Lebanon, Syria, Iraq and Iran: give Islam an inch and it’ll take a mile. Only uncompromising secular rule will prevent chaos leading to theocracy. This means an iron heel crushing every attempt by Islamists (i.e. Moslems who are serious about the Koran) to put their heads above the parapet. A lesson to be learned in Australia. The trick is to make sure the iron heel is not as great a menace to liberty as Islam. To do that requires struggle and cultural (r)evolution as in Europe, Britain and North America. Turkey seems to have gone a long way towards combining (regrettably unstable) democracy with ruthless exclusion of Islam from any function of government. Iraq did keep the Moslems in their place even though without democracy. Now, courtesy of the horde of lying war criminals led by Bush, Bliar and Howard, Moslems are running rampant in Iraq and will continue to do so.

A good review of the situation, except he missed a salient detail.
ISIS is the bastard child of Saudi Arabia's religious denomination, the Wahabi's.
They've been the recipients of vast oil fortunes, and have been funding Fundamentalist schools all across the world, it was this early schooling that led to the Taliban, now that movement has birthed the ISIS.
If ISIS manages to establish a viable Caliphate it will inevitably come into conflict with the existing Muslim and Arabic nations power structures.
And unless they unite to wipe it out entirely and brutally, they'll lose.
I know of no way of predicting the outcome of the current situation though, it's all guesswork, even for the "experts".