I see the terrorist group currently overrunning Iraq has promised to occupy Saudi Arabia and destroy The Ancient House, the Kaaba, the holiest site in Islam. That is not likely to sit well with the reset of the Muslim world.
If they succeed they are likely to shatter their own religion, which in large part depends on the fellowship generated by the Hajj, the pilgrimage to Mecca and the Kaaba, for the glue that binds the faithful together.
Of course, Iraq’s basic problem is the bitter divisions between Muslim sects. When the Brits created Iraq they created a melting pot, with no dividing lines between territories controlled by mutually hostile segments of society. All sides, there are more than two, claim supremacy, in a land where there are no natural features such as mountain ranges to separate the factions.
As an artificial construct, Iraq’s day may be done. I think it likely that we will see a migration of the Sunni to the West, the Shia to the east, and Satan take the hindmost. And after that, the real privation and suffering begin.
But if I read the history and human nature aright, ISIS has just made it extremely difficult to succeed in Iraq. And very much less likely to succeed in Saudi Arabia, where it can expect a hostile populace, and well armed resistance.