It was a mistake. On the information we had, we shouldn't have prosecuted the war. We shouldn't have changed our argument from international law to regime change in a non-transparent way. It was an error for which we as a country paid a heavy price, and for which many people paid with their lives.
Getting rid of Bin Laden is good for the cause of peace worldwide but what counts is to overcome the discourse and the methods - the violent methods - that were created and encouraged by Bin Laden and others in the world.