Amy Zegart, who is guest-blogging for Volokh, asks Why Haven't We Been Attacked Since 9/11?:
Just because we haven't experienced tragedy does not prove we are doing things right. This is causality 101, and it's something we drum into UCLA MPP students in their first year. Causal connections have to be examined, not assumed, or you'll get into trouble.
My 92 year-old grandmother, whom I love dearly, still drives a car in Miami. Incredibly, she's had no accidents since 9/11. But I'd never conclude that her driving acumen is responsible for her traffic record, or that she's become a better driver over the past 6 years.
The "we haven't been attacked" argument suffers from the same logical weaknesses. Why haven't we seen another 9/11 since 9/11? A million possible reasons. Many it's al Qaeda's long planning cycles. Maybe it's the disruption of al Qaeda Central in Afghanistan. Maybe it's sheer dumb luck. Maybe it's those ziploc bags at the airport. But the most dangerous explanation is the one that works backwards, inferring causes from outcomes and suggesting success when there may be none.
Who knows, perhaps it is that our security folks have really Gotten Serious and are catching all sorts of terrorists. But it seems to me that the more likely explanation is this: we don't have as many Muslims as Europe, and these days, we're letting in a lot fewer than we used to. And the Muslims we do have are, by and large, much better integrated than those in Europe.
I'm very fond of America's policy towards immigrants, which is to say, we don't have one. No one will try to force you to assimilate, but no one's going to help you keep from assimilating either. This policy of benign neglect considerably alleviates both sorts of Muslim/Christian tension found in Europe: the populations that have been positively encouraged not to see themselves as part of the larger culture, and the populations that feel their traditions are under attack. Obviously, it's not as if America is some sort of perfect paradise where no Muslim kid ever feels either excluded, or forced to assimilate. But the sharp group-on-group rage never seems to have gotten a foothold here. And of course, America in general has much more experience assimilating strangers than Europe.