How much liberty should we be willing to give up in order to make ourselves safe from terrorist attack? Few deny that some trade-off is necessary. The terrorists who attacked New York and Washington on September 11, 2001, took advantage of the liberties we enjoy and some of those liberties need to be curtailed if other terrorists, following their example, are not also to take advantage of them with similar or even more terrible results.
But trading off liberty against security has a treacherous logic. It beckons us in with easy cases—the trivial amount of freedom restricted when we are made to take our shoes off at the security checkpoint before we board an airplane is the price of an assurance that we will not be blown up by any imitators of Richard Reid. But it is also a logic that has been used to justify spying without a warrant, mass detentions, incarceration without trial, and abusive interrogation. In each case, we are told, some safeguards and rights that were formerly regarded as civil liberties have to be given up in the interests of security. But after a while we start to wonder what security can possibly mean, when so much of what people have struggled to secure in this country—the Constitution, basic human rights, and the rule of law—seems to be going out the window.
When logic betrays us, we have to retrace our steps—sometimes in a fussy and pedantic sort of way. So let’s think carefully about the trade-off between liberty and security. One crucial distinction is between trade-offs involving only our own personal situations and interpersonal trade-offs involving others.
A simple case of a personal trade-off is this. I accept the burden of a legal requirement to wear a seatbelt, restricting my freedom to sit in my car as I like, because I am convinced that this will make me safer, less liable to injury or death in the event of an accident. If we all do this, then each of us is safer though each of us is a little less free. We can think of it as a straightforward trade-off, once we understand what happens to human bodies in automobile collisions. It’s something like buying more potatoes (safety) and less meat (liberty) when we find that meat is more expensive than we thought.
Another similar case, slightly less straightforward, is when we all accept a restriction on liberty not because our own actions pose a threat to our own safety, but because it is possible that some of us may pose a threat to the others and we don’t know who. This is the logic of the airport security system; and it too seems to make innocuous sense. We all accept certain restrictions in the expectation that we will all enjoy greater security. Again, the trade-offs affect our own well-being: each of us bears the cost and each of us reaps the benefits.
Quite different, however, is the …