Tradeoffs in Airport Security

In the immediate aftermath of a terrorist attack on an airplane, there are always calls for increased airport security measures. Some of the proposed new measures may be justified, though others are likely to be “security theater.” But even security measures that do increase safety create difficult tradeoffs that we don’t think enough about. Law professor Bradley Smith properly emphasizes this important point:

[A] good question is inadvertently raised [by DHS Secretary Janet Napolitano’s statement that “the system worked”]: what price are we willing to pay for more security? No system is foolproof. If by “the system worked” Secretary Napolitano merely meant that “the system” prevents most such incidents at a reasonable cost, and realistically we cannot prevent all incidents at an acceptable cost, that would be a serious argument worth considering. Americans don’t want to hear that, or course, especially in the immediate aftermath of a near disaster.

Eight plus years after 9/11, the question we have yet to really discuss honestly as a society is this: how much are we willing to pay in time, indignity, discomfort, loss of freedoms and privacy, and cash outlays in order to reduce the probabilities of attacks occuring? This is not an easy question, in no small part because it is extremely difficult to know how many incidents are being prevented by our current security measures, how many more could be prevented by further security measures, and how many more might have occured if we didn’t all have to stand around taking our shoes off in airport security lines.

An understandable kneejerk reaction is to say that no price is too high to pay for saving lives. But a moment’s reflection suggests that isn’t true. For instance, let’s say that we could reduce terrorist attacks on airplanes to zero by subjecting every passenger to a strip and body cavity search, and having all baggage searched by hand. Most people would still conclude that the benefit isn’t worth the cost in resources, lost time, dignity, and privacy.

An important related point is that we should not impose severe burdens on air travelers whose main effect is simply to divert terrorists to other, “softer” targets. Even if costly and intrusive measures succeed in providing perfect security for airline passengers, they still would not be worth it if the terrorists simply switch to other targets that are comparably attractive from their point of view. In Europe and Israel, the terrorists have reacted to improvements in airport security by attacking trains, subways, university campuses, and other areas where large numbers of people gather in places that are harder to secure than airports and planes. That doesn’t mean that we should have no airport security at all. But it is a factor that weighs against adopting extremely costly and/or highly intrusive security measures. Even if such policies reduce the risk of terror attacks on planes, they still may not be worth their cost because they might fail to reduce the net loss of life caused by terrorism overall.

Similarly, if we impose too many hassles on airplane passengers, more people will travel by train or bus, both of which are much easier for terrorists to attack than aircraft are. Others might choose to make long trips by car. Cars rarely make good targets for terrorists. But traveling a given number of miles by car exposes you to a much higher risk of death or injury by ordinary accidents than traveling the same distance by plane. Again, the net impact might actually be to increase loss of life rather than reduce it.