Twelve years ago, George W Bush gave his "Mission Accomplished" speech from the flight deck of the USS Abraham Lincoln aircraft carrier, confident that the Saddam Hussein regime had been consigned to the dustbin of history, the Taliban regime had been terminated, al-Qaeda was dispersed, if not destroyed, and the desperately needed New American Century was back on track.
That's what he thought. Instead, over the following decade, hundreds of thousands died in the wars in Iraq, Afghanistan and Libya.
War is good for Isis. It relentlessly portrays itself as the defender of Islam under attack from crusader forces as it creates a rigid and determined caliphate, a pernicious world view hated by the overwhelming majority of Muslims - yet appealing to a tiny minority that is still worth proselytising.
Until last spring, IS concentrated primarily on developing and protecting its proto-caliphate. But it has now extended its operations overseas.
This has taken two forms - developing connections with like-minded groups: whether in Libya, Nigeria, the Caucasus, Afghanistan or within the Middle East - and fostering direct attacks on the "crusaders", whether it's the tourists killed at the Bardo Museum and the Sousse resort in Tunisia or, more recently, on the Russian Metrojet, and during the horrific attacks in Paris last weekend.
As Isis no doubt hoped, France has reacted with renewed air strikes in Syria, and across the West there is talk of an expanded air war and even the use of ground troops. This will be music to the ears of the IS leadership. Some of them will be killed but what does that matter when they are part of a divine plan? Moreover, if their acolytes can carry out more attacks then there is a real chance of rampant Islamophobia evolving rapidly with all the recruitment potential that it provides.
What should the West do?
If we follow the logic of Isis wanting war and suggest quietly that it might not be a good idea, then the inevitable response is: "What should we do?".
An early priority is putting far greater emphasis on ending the Syrian civil war, the necessary precursor to constraining IS in Syria. There are some small signs of progress here, but the process must be accelerated and, however difficult, Assad and key militia leaders must somehow be engaged. It is the most difficult of all the tasks and will require the best skills of highly competent conflict resolution specialists.
Close behind that in importance will be a huge and immediate effort to aid the three million or more refugees from Syria and Iraq, principally in Jordan, Lebanon and Turkey. The core motive must be humanitarian - but if help is not provided, these camps also will provide a remarkable recruiting ground for IS.
A third element is to work as hard as possible to encourage the Abadi government in Baghdad to reach out to the Sunni minority, especially in those many parts of Iraq where persistent neglect of that minority is helping maintain support for IS.
Finally, there is the issue of the expansion of Isis, not least in Libya. The need to support UN attempts to bring stability to that country is urgent yet seriously lacking at present.
In this context, perhaps the most urgent need for any state seriously interested in preventing the further growth of extreme Islamist movements is to foster a change in the repressive policies of the Sisi government in Egypt. With more than 1000 Muslim Brotherhood supporters killed and well over 10,000 imprisoned this is the one country that is ripe for Islamist expansionism.
None of these measures provides anything like a full answer to the many challenges of IS but they collectively point us in a different direction. If we do not take a new direction then we should prepare for a 30-year war.
Paul Rogers is Professor of Peace Studies, University of Bradford.