I have never completely agreed with the recent war(s) in the middle east, but IF we are able to bring true safety, fair equitable treatment/freedom, and fair/free education (among other things but I feel those are some of the most important things western society has to give to the world), THEN we can truly say "mission accomplished." Also, IF we are starting to have a negative impact, to the point that we are stirring up more terrorists against us by poor tactics or just the simple fact that we are occupying their territory, THEN we should leave. Unfortunately, it seems like leaving (especially if we leave before those goals are accomplished) would only stir up even more enemies.
Our nation hasn't had a very good history when it comes to international relations, especially in the middle east. As I said before that we are, in some way, responsible for provoking the unrest that we are now trying to quell. Maybe we shouldn't have done some of the stuff we did to provoke the unrest, but in some ways we just did what we thought was right at the time without much of a view for the future. Hopefully, we can make up some of that wrong and bring true help to those we've mistreated in the past.