The question is a fair and natural one to ask, and I’d like to examine it in depth. I think my intuitive answer (“revelations about wiretaps don’t help the terrorists”) is wrong, and that there are surprising effects of revealing investigative measures. Further, those are effects I haven’t seen discussed. Allow me to explain the logic.
First, terrorist organizations need to communicate on a wide variety of levels, from ‘moral support’ to target selection and dates. Second, we can wiretap all their communications, under a variety of legal standards.
So, should we talk about wiretapping of terrorists? The President has asserted that it ‘helps the terrorists’ in some way. Lets ask how that might be. Does talking about wiretapping help the terrorists? Revelations of wiretapping cause both awareness and fear. Either or both could lead to temporarily improved communications security process. What could those be? New crypto? New attention to detail? Better shredding? There are others, which I’ll talk about in a minute. For now, let’s work with the assumption that revelations lead to better adherence to security processes, and the second assumption that better security processes are bad for the listeners. Let’s take those two benefits one at a time.
The first is enhancing terrorist awareness of their threat environment. This is important. As time passes, people become complacent. As they become complacent, their investment in security processes drops off. (There are lots of interesting analogies to this in the business world.) Complacency thus helps the attacker, and hurts the terrorist. So revealing our wiretapping, reducing complacency, hurts the eavesdroppers. Unfortunately for the eavesdroppers, the terrorist exists in a highly adrenaline-filled environment, with regular revelations that his colleagues have been arrested, tortured, or assassinated. Each and every one of these events causes the terrorist to assess his security posture. So, our first assumption (revelations lead to better adherence to security processes), while true, is but one of many causes for that adherence.
Improved communications security is not the only effect of the revelations. What happens if a terrorist is already under surveillance? They may go to ground, or they may reveal alternate communication methods (phone numbers, email addresses, web sites) not yet known. Their security processes presumably include backup methods, and driving those methods into the view of the security services is an important goal.
At this point, we have something of a balance between two hard-to-quantify ideas: better operational security versus the value of exposing alternate channels. There is, however, one final effect of driving terrorists to ground, and it tips the balance.
The final piece is that al Qaeda terrorists gone to ground do not engage in attacks. That gives the investigative services more time to find and arrest them. To me, that tips the balance. Whatever benefits accrue to the terrorists through bless complacency are balanced by exposing additional channels. Delaying murder, and giving us another chance to prevent it tips the balance, even before the benefits of the rule of law are brought in. So! Bring on the revelations!
[Update: Yes, that’s the original poster, with the word “might,” as it appears at archives.gov.]