The key to answering a question is in understanding the terms. This may not be possible for your question. I believe that Iraq is a game with "hidden variables". Our government doesn't have all the cards on the table regarding want they want and from whom. Sadam was a very bad man. That said, I can't believe that the Administration pushed for the war, and ran it the way they did, just because there was a dislike for Sadam.
What do we do now? The hidden variables come into play. What do the decision makers really know? Now I believe we have a situation of regional stability. We would love to exit Iraq, but to do so would allow the region to destabilize. There may be greater minds than us that know just how bad it could it. Part of me finds this hard to believe, as those 'greater minds' also got us into this mess. The right path forward would be one that insures relative stability of the region.
I don't fully buy the "eliminate a breeding ground for terrorists" line. Britain is a breeding ground for terrorists, but we're not invading them. Ok, that's an extreme example. The point is that there are many other countries, including Saudi Arabia, in which terrorists are made.
A popular thought now is to send more troops. The posting of more American troops can have a sum-negative affect. The fact that we have a soldier on every corner may lull the day, but the sentiments stirred by that show of force may not be helpful in the future. I believe we are in a "least pain for maximum effect" scenario. Can we trust the Iraqi government to hold the country stable if we pull out? How much can we pull out for that to happen? When? I believe this is "what to do about Iraq" that our policy makers are pondering.