We actually already have a very good framework for deciding if the number of lives saved by a given program will be worth the expense compared to other things we could be doing with the same money, the Office of Information and Regulatory Affairs. This isn't applied to defense issues, but I can very much see it being applied to things like terrorism or crime:
There's also the fact that air travel restrictions probably cost lives on net, because the number of people encouraged to drive instead of fly who then go on to die in traffic accidents almost certainly exceeds the number of people they save from terrorist attacks.
I think it would be enormously enlightening to calculate the estimated cost-per-life-saved of various elements of the anti-terrorism budget, and compare it to alternative programs that could have used the money.
When it comes out to be in the billions-per-life-saved range for anti-terrorism while alternatives like cancer and heart disease research and treatment come in at thousands-per-life-saved, maybe people will get the message.
http://www.slate.com/blogs/moneybox/2013/06/08/counterterror...
There's also the fact that air travel restrictions probably cost lives on net, because the number of people encouraged to drive instead of fly who then go on to die in traffic accidents almost certainly exceeds the number of people they save from terrorist attacks.