In 2013, American and British public opinion said "hell no" to plans to bomb (and surely regime change) Syria, taking the momentum out of the march to war. This marked a peak in post-Iraq war-weariness. But then in August 2014, many hearts were touched by the plight of a group of Yazidis trapped on a mountain and besieged by ISIS. So public opinion sanctioned a humanitarian military rescue. During the operation, it was revealed that the crisis was blown way out of proportion, as excuses for war so often are.

Predictably, ISIS retaliated. The group posted snuff films depicting the beheading of western journalists. American outrage was intense enough to allow President Obama to essentially launch a new war on ISIS. And since ISIS was in Syria as well as Iraq, this provided cover for American planes to enter and bomb Syria after all. This too elicited retaliation, in the form of ISIS terror attacks against civilians on western soil: in France, the U.S., Belgium, and elsewhere.