Since I saw the Trade Center fall in person (not on screen) I am unable to go "La la la they can't strike us here" and believe myself. Nor do I believe that recent history predicts the future. The main players in Islamic State are far more radical than Osama ever was. Osama was one nasty piece of work who deserved killing, but he wasn't pure evil. His main goal was a "purer" Saudi Arabia without so much US influence. These fucks have as their goal an Earth purified of all who don't share their exact beliefs. Osama was dependent on funding primarily from his friends among the Saudi princes, who insisted on some degree of moderation especailly after 9/11 when they got back-channel messages that we'd come after them next if not; these fucks control their own oil fields, and depend on no other nation as long as they have markets for their oil.
We're can obliterate them now, while they're relatively local, or nuke 'em later, by which time they'll have cells trained and equipped throughout the First World. Our Iraq experience is not what we should be learning from. Iraq needed to be successfully occupied and turned around. We were terrible at that. Islamic State merely needs to be utterly destroyed. That's within our scope. Osama wasn't the threat we thought he was; these fucks are the threat we thought he was. We must abstain from restraint in their obliteration, unless we're ready to tolerate far worse in terms of terrorist attacks than 9/11 ever was.
I say this as a left-wing, pro-Palestinian admirer of Ghandi and MLK. The US might have done well to stay out of WW I, but if we'd stayed out of WW II the world would have been ruined. The US would have done well not to start Iraq War II, but if we hold back from a strategy for full victory over the Islamic State, civilization's odds are not good. If we leave them intact for long enough to attack us here - which they will - say goodbye to what's left of our civil liberties.