Level the whole damn city.
Let it be known that ISIS will not be allowed to exist in the confines of any city. If they show up, the city is doomed.
That way the residents of any city where they may show up will be properly motivated make sure they aren’t allowed to stay.
Destroy the oil fields they control in Iraq. They are making millions of dollars a day and are financing a lot of things with this money.
Arm the Kurds and any Christian militias that are left.
Bomb their mosques. Kill their religious/political leaders.
The problem with the migrants is there is no way to verify any information on them. Whatever they tell you their name is you have no way of knowing if it's true or not. Send them back unless you can verify (how) that they are Christians fleeing persecution.
That way the residents of any city where they may show up will be properly motivated make sure they aren’t allowed to stay.
Simple, but effective plan.
I would suggest the following: On day one we announce that on day three the city will be leveled. If you are ISIS you will die. If you are not ISIS it is suggested you leave or you will die. They will not believe you and most will stay.
On day three announce that you lied and use neutron bombs instead. Everyone there will die and you do not destroy a perfectly usable city.
They will not die immediately but they will die and it will be brutal and agonizing. The enemy understands this kind of action.
On day four repeat as necessary.
War is a brutal and ugly thing. When at war with a committed enemy their is no negotiation possible as their commitment is fanatical. This was the case with the Japanese. Two atomic bombs changed their fanaticism.
He who is not ready to kill his enemy and all that stand with him is destined to defeat. He who will kill his enemy and all that stand with him will not need to as his enemy will not raise his hand in anger against him for fear of losing his life, his family, his country and all that is dear to him or her.
Our military is the finest killing machine in history. When you put limitations and insane "Rules of Engagement" on them they are not longer this perfect machine of death. As such our enemies will engage us. The best military is one that is never used because your enemy knows to engage it is certain death.
What’s really going on there. The Russians have supposedly been bombing the crap out of the Muslim Brotherhood when Obama didn’t properly bomb the crap out of the Muslim Brotherhood, now France just strolls in and bombs the crap out of them. How are all these targets so easy to find if they’ve been getting the crap bombed out of them. Something smells funny about the whole entire war campaign going on over there.