The chances of my being involved in a terrorist incident are less than the probability of being involved in a home invasion, or a carjacking, or a road rage incident. I own a gun, partially to protect myself from criminals, but I also recognize I am more likely, statistically, to shoot myself accidentally or commit suicide than I am to defend my home from an intruder with a firearm. Sure, we all say “That won’t ever happen to ME”, but everyone who it has happened to probably rationalized it that way. There is a risk of perishing from a number of different crimes and accidents, but we cannot fully protect ourselves from all of them all the time. In fact, being overly paranoid can just make things worse.

Does this mean we should do nothing about terrorism? Of course not. Our chances of being involved in an aviation accident are miniscule as well, but we still insist that the proper regulation and monitoring of air travel and aircraft maintenance and crew training be maintained. We wear seat belts and enforce traffic laws.

We need to take precautions against terrorism as a society, because it is the role of government to protect us from these dangers, and because it does impose a real cost to the whole society even though very few of us are actually affected. We reduce these risks by taking security measures, by law enforcement, and by diplomatic and military action. But we also run the risk of paying a greater cost (due to our precautions) and in the loss of our personal liberties than are at risk from the terrorists.

The key to this sort of effort is cost/benefit analysis. We must take steps to protect ourselves by making the most likely catastrophes much less likely, but there will always be catastrophes and we can never guarantee to reduce that likelihood to zero; and to attempt to do it is often counter productive, or can introduce dangers of its own (seat belt injuries, faulty air bag deaths). The C/B analysis is often flawed, or based on insufficient data, these risks are, after all, very low probability to begin with and data is spotty. But we must use common sense, and above all, avoid reacting from fear.

Terrorists acts are scary and dramatic. After all, that’s why they are called terrorism. We must take reasonable steps to reduce them and to punish the perpetrators, but we should not react irrationally. That is part of the terrorist program; yes, it is a cliche, but they really do win when we overreact. The cost to the society of responding to a bomb threat can exceed the cost of cleaning up the mess after a real bomb.

But it is an election year. And the deliberate exploitation of fear for political purposes is also a consequence of terrorism, and serves the purposes of terrorists. In a way, it is also a form of terrorism: the use of terror to bring about a political change.