Paul Krugman has written a really good update of my 2006 essay.

Krugman:

So what can we say about how to respond to terrorism? Before the atrocities in Paris, the West’s general response involved a mix of policing, precaution, and military action. All involved difficult tradeoffs: surveillance versus privacy, protection versus freedom of movement, denying terrorists safe havens versus the costs and dangers of waging war abroad. And it was always obvious that sometimes a terrorist attack would slip through.

Paris may have changed that calculus a bit, especially when it comes to Europe’s handling of refugees, an agonizing issue that has now gotten even more fraught. And there will have to be a post-mortem on why such an elaborate plot wasn’t spotted. But do you remember all the pronouncements that 9/11 would change everything? Well, it didn’t — and neither will this atrocity.

Again, the goal of terrorists is to inspire terror, because that’s all they’re capable of. And the most important thing our societies can do in response is to refuse to give in to fear.