"Work expands to fill the time available for its completion," wrote Cyril Northcote Parkinson in 1955, and instantly created a whole new domain in the study of human affairs. "Parkinson's Law" was one of the most profound insights of the past century, but he didn't go far enough. There is a media corollary that doesn't get nearly enough attention.
It is this: "International confrontations expand to fill the media space available." There is a lot of media space available nowadays, and a striking shortage of truly terrifying international threats, so the few modest ones that do exist are magnified to fill the scary news quota.
That's why you hear so much about the North Korean nuclear threat, the Iranian nuclear threat, and the international terrorist threat. Unless you live in South Korea, or Israel, or lower Manhattan, none of these "threats" will ever disturb the even tenor of your life - and even if you do live in one of those places, it is still very unlikely.
The very unlikely did happen in lower Manhattan once, 12 years ago, but it is very, very unlikely to happen there again. Nevertheless, 9/11 is used to justify an ongoing "war on terror" that has provided long-term employment for several million people and justified well over $1 trillion in "defence" spending over the past decade.
Which brings us to another law, the Shirky Principle: "Institutions will try to preserve the problem to which they are the solution." In other words, armed forces, intelligence services and those parts of the foreign policy establishment that have prospered from "fighting terror" will instinctively preserve that threat. They hunt down and kill individual terrorists, of course, but they also keep coming up with new terrorist threats.