"The terrifying cost of feeling safer," from the Sydney Morning Herald:

Sandler and his colleagues conducted an analysis of the costs and benefits of five different approaches to combating terrorism. I must warn you that, because of the dearth of information, this study is even more reliant on assumptions than usual. Even so, in three cases the cost of the action so far exceeds the benefits that doubts about the reliability of the estimates recede.

Because the loss of life is so low, they measure the benefits of successful counter-terrorism measures in terms of loss of gross domestic product avoided. Trouble is, terrorism does little to disrupt economic growth, as even September 11 demonstrated.

Using the case of the US, Sandler estimates that simply continuing the present measures involves costs exceeding benefits by a factor of at least 10. Adopting additional defensive measures (such as stepping up security at valuable targets) would, at best, entail costs 3.5 times the benefits. Taking more pro-active measures (such as invading Afghanistan) would have costs at least eight times the benefits.

According to Sandler, only greater international co-operation, or adopting more sensitive foreign policies to project a more positive image abroad, could produce benefits greater than their (minimal) costs.

What's that? You don't care what it costs because no one can put a value on saving a human life? Heard of opportunity cost? Taxpayers' money we waste on excessive counter-terrorism measures is money we can't spend reducing the gap between white and indigenous health -- or, if that doesn't appeal, on buying Olympic medals.