IMO such a course of action would worsen the terrorist situation. Going in without having trained a governing body outside first and make certain it is operating will only fuel more unrest. Also - while I am not a stickler for blind obedience to law, and international laws have a lot of stupid assumptions in them - going in there without a UN mandate just because a couple of US citizens (lets say between 10**2 and 10**3) were killed by multiple terrorist actions would be hypocritical if you set that # into relation to the estimates of non-combatants killed by the US in the last decade over there. Just to be clear: when Afghan circles declined to support US going after Al Qaida, I supported the military action, including german active support.

ISIS is growing in strength every day. So how do you propose that we stop them? Or do you think that we should just leave them alone?