The politically correct crowd insists that Islam is a religion of peace. They are wrong. Anyone who has spent even a modest effort to read the Quran and study the life of Mohammad will understand that the root of Islam is steeped in violence, war, and retribution. Those that are not Muslim, and more specifically, not of the worshiper's Muslim sect is an infidel. Infidels may be killed or enslaved.
Over the centuries, many Muslims have adapted there religion to the established laws of the country in which they reside. They are still schooled in Shariah Law and many practice it within their own communities. Most realize that if they cut off the hands of a thief, they would run afoul of the civil authorities. To most, that sacrifice would be too great, so they "render unto Caesar". They find the comforts of Western Civilization are easily adapted to and enjoyed in this more modern age.
There are, however, many that prefer the fundamentalism of the ancient ways. They find that the literal Quran and the life of the Prophet are the only true Islam. All else is apostate. To act entirely in this manner, in most of the world, would make one a criminal. To act this way continuously would bring down the wrath of local authorities.
As the world has borders, and within those borders civil governments rule their territory as they see fit. Fundamental Islamists have a problem. Even in their own Middle Eastern countries, excesses would not be tolerated. So their ancient religion came up with an ancient solution.
Enter the Caliphate. Osama bin Laden talked about the Caliphate. But his vision saw it far in the future. After 9/11 bin Laden took to running and hiding. He did not have the means or the personal security to organize the new Caliphate.
Abu Omar al Baghdadi took over al Qaeda in Mesopotamia and united other disparate groups to form, what we now call, ISIS. He declared ISIS the new Caliphate. Young fundamental believers flocked to him. Not because they didn't have jobs, as our State Department would have us believe, but because they were true believers and wanted to fight for Allah and Islam or because they were drawn to the opportunity to commit violence. They were perfectly willing to become martyrs for the cause.
To Muslims that join ISIS, state borders no longer matter. The Caliphate transcends the state. Sharia Law can be practiced with impunity for it is the law of Islam. It is their intent to kill the infidel and rule the world. That was the right and obligation they were given by Allah in the Quran.
To defeat them, we, the Western World, must recognize that we are not fighting a geographical enemy. We are fighting an ideological enemy that is fully wrapped in a religion. Our leaders may make light and say they will not fight a "whack-a-mole" war. But they had best get around to identifying our enemy and the type of war that must be fought. And they need to do this quickly. If they do not take control of the situation, much more of our blood will be spilled. Then, we must have skilled war fighters decide how to win this war. This task is far above the skill level of a neighborhood organizer.