ISIS is jerking us around by beheading another hostage. What these jerks are trying to do is get us to start up the Iraq war all over again.
Somewhere in history I remember reading that when the Allies were pounding the Third Reich from the air, a German general said:
Our only hope is that they will come somewhere where we can use the army on them.
That's exactly what's going on here. These ISIS goons want to have their own little day of glory, every day, turning what's left of Iraqi civilization into a guerrilla warfare hell, because, like the German Wehrmacht, that's where they're strongest and we're weakest.
Let's not play their game. Cut off their money (Qatar and Saudi Arabia, I'm looking at you), recognize Kurdistan (and arm) as the independent state that it practically is now, and let ISIS burn itself out.