But one of the things that I fear about the current sort of political conversation is that when it comes to dealing with the immediate threat, lots of people don’t do their homework about Islamism and the ideology that ­animates Al-Qaeda. We could all form a judgment about what was required in order to make our societies more resilient and we might reach a consensus there but unless politicians are aware of what the ideological wellspring of these attacks is, unless they are aware of what the authentic root causes are and what the bogus root causes are then we are likely along the way to make mistakes that will only make our lives more difficult.

PB: I don’t think right now any of the great states that are combating terrorism integrate that tactical strategy with a larger grand strategy. We tend to think about grand strategy as a matter of inter-state conflict because it has been for five centuries. So when people write about geopolitics or geostrategic visions, terrorism is more of an annoyance than it is part of the large landscape. I think that’s a mistake. When I was working in the Carter Administration I was living a few blocks away from the White House and one of my classmates from law school came to visit. Every morning he would walk me to the White House just to chat and accompany me. He had been an architecture student as an undergraduate at Harvard and as we’d walk along I’d be staring at the cement thinking about what was happening in the office and he would try and get me to look up to point out the architraves and the facades of these beautiful buildings.

Well, he was there for a week and for four or five days after he left I would walk to the House and I would look up at these lovely buildings. Then I noticed that every day after he left my eyes got lower and lower and lower until finally a week later I was back to staring at the cement again. I think there is an almost irresistible pull for people in government away from the horizon and towards the next step. It is very hard to combat. With a problem as novel as this, if we don’t raise our sights we run the risk of taking decisions; decisions that look so much like each other from a close perspective but they will take us to completely different worlds five or 10 years down the line. We look at decisions as we look at our shoes. They seem separated by trivial distances but when played out and set into motion, bureaucracies, budgets and alliances can just as easily entrap us as empower us.