As it is now there aren't that many ISIS troops that are over there perhaps 5000 or so. As I suggested before about arming the terrorists in Syria to fight the dictator wouldn't be a very good idea and now you see why. Most of the weapons that would have been sent to the terrorists would have ended up in ISIS hands because ISIS troops are better at getting things done and would have stolen those weapons to be used against all those opposed to them as they are doing now.
So the Iraqi military isn't doing much to protect its own interests and have run away from the fight. Why should American troops help a country that won't help itself?