Sun Tzu wrote in Chapter 8 of The Art of War: “Do not depend on the enemy not coming, but depend upon our readiness against him. Do not depend on the enemy not attacking, but depend on our position that cannot be attacked.”
The real battle is internal (on a number of levels). Do not be moved by appearances. Do not give in to the hype. Prepare your own mind, body, and spirit for the challenges and challengers on the horizons of your awareness.
As for the IS threat, first and foremost, do not take anything at face value, perceive that which cannot be seen, as Musashi advised in the Go Rin no Sho. This means, look behind the IS front and see where their strength really lies. In war, it is not so much about tactics as it is about logistics. So, follow the money and see who is providing IS with the vast material resources necessary to carry out a belligerent campaign.
Next, look at who or what opposes your own personal readiness and the creation of your own position that cannot be attacked. How can you cultivate your own invulnerability? What obstacles must you overcome? Can you acquire the tools, resources, and means of resilience? What stands in your way?
What policies are enforced (and by whom) that leaves airline passengers and pilots vulnerable to box cutters? What policies are imposed upon a population (and by whom) that leaves soldiers and women vulnerable to machete wielding attackers in the streets? How can you overcome these defense defeating policies?
Sun Tzu wrote in Chapter 1 that the means of victory come from calculation; in other words correct diagnosis of the threat. Fighting the last battle, such as most bureaucratic militaries have done over the past century, is a demonstration of incorrect diagnosis.
Overcoming the potential for embroiling in yet another ill-conceived and poorly executed quagmire requires correctly diagnosing where the real threat resides. Look at results, not intentions. Quantify, measure, and establish facts. Following the financial and logistical train behind IS and identifying who (or what) stands in the way of building local readiness, is the key task.