Stephen Walt sees  the U.S. repeating past mistakes in its war on ISIS. The first mistake he identifies is the tendency to exaggerate foreign threats:
Why is threat inflation a problem? When we exaggerate dangers in order to sell a military [action], we are more likely to do the wrong thing instead of taking the time to figure out if a) action is really necessary and b) what the best course of action might be.
It’s fair to say that U.S. officials wouldn’t have to exaggerate foreign threats so often if military action were clearly necessary. The U.S. is an extraordinarily secure country, so it requires an extraordinary amount of dishonesty and exaggeration to convince Americans that launching attacks overseas is necessary for our security. Government officials have to overstate threats from overseas in order to justify military action that they all know isn’t strictly necessary, and so they also overstate how many interests the U.S. has in the world and exaggerate how important those interests are. All of a sudden, the U.S. is defending supposedly “vital” interests in places that have no importance for American security whatever. The assumptions behind preventive war also give each administration greater leeway. These allow presidents to dismiss the lack of evidence of a direct threat right now because of a belief that a threat might materialize later on. The slightest possibility that there could be a threat at some point in the future is treated as if there definitely is one, and so the U.S. starts bombing another country. It doesn’t matter that the U.S. isn’t actually threatened by the government or whichever group is being targeted. All that matters is that the U.S. has responded to the overblown threat with “action.” Bombing the supposed future threat becomes self-justifying, and self-defense is expanded to mean whatever the government wants it to mean.