But what if, (as long as we are playing with people's lives) despite our best efforts, something else like 9/11 or worse happens?

You mean like

• Europe becoming a suitable habitat for the malaria mosquito?

• A major coastal city being wiped out by natural disasters in a nominally first world country?

• A million or so people incarcerated in nominally first world countries for trivial non-violent crimes?

And the funny thing is that I conclude this based on largely the same line of argument that you use to justify making it an issue: It is so ridiculously easy to make a major kaboom somewhere in a Western(TM) society where it will hurt badly. If there were slavering hordes of terrorists out there whose highest ambition in life were to make the lives of Western(TM) citizens and/or countries difficult, stuff would blow up every other month. It doesn't, so there aren't.

The Danish resistance during the War (which wasn't particularly impressive) managed to blow up more stuff in Denmark over two years than Al Qaeda's goons have managed throughout Europe since the founding of the organisation.

Can we please stop being scared now?

- Jake

If you only spend 20 minutes of the rest of your life on economics, go spend them here.