Justifying homeland security spending

Using math, naturally. John Mueller and Mark Stewart construct a model for evaluating the cost of increased security since 2001. I'll spare you the statistical arguments – which are all very interesting – and skip straight to the conclusion:

Risk reduction measures that produce little or no net benefit to society or produce it at a very high cost cannot be justified on rational life-safety and economic grounds: They are not only irresponsible, but, essentially, immoral. When we spend resources to save lives at a high cost, we forgo the opportunity to spend those same resources on regulations and processes that can save more lives at the same cost, or even at a lower one. Homeland security expenditure invested in a wide range of more cost-effective risk reduction programs like flood protection, vaccination and screening, vehicle and road safety, health care, nutritional programs, and occupational health and safety would likely result in far more significant benefits to society.