Wampum

Ted Barlow at Crooked Timber has a hard time figuring out how the leak of classified information regarding the lawless, warrant-less wiretaps of American citizens harmed national security as many have claimed:

In the case of the NSA leak, I'm afraid that I don't understand how it compromised our national security. In this comment thread, Professor Althouse writes:

There is reason to be more outraged (by the NSA leak over the Plame leak), because of the actual damage to national security. Ever think about that?

Unfortunately, she doesn't elaborate about how the leak compromised national security. It isn't obvious to me; I don't understand how it would help a terrorist cell to know that their communications were subject to monitoring without warrants, versus with warrants. It's not as if the leakers revealed "specifics about TSA strategies..., including specifics about how terrorists tend to react to the types of questioning at issue," for example.

Please to click through to the Philosorator link about published information that could well cause actual harm to our efforts to thwart terrorists. You will not be disappointed.

I think that it is plausible that the leak had a small harmful effect on national security. When trying to assess that effect, it is important to balance harm with associated benefit to arrive at net effect. The reason that is important is that for each potential harm that I consider, it appears that there are associated national security benefits. All the effects appear to be at the margin, and to get an accurate picture of the effect on national security of the NSA leak, we should focus on the balance between the bad and the good.

Any harm to national security must come by way of the terrorists changing their actions as a result of the leak. President Bush has made clear that he is not changing his. Obviously, if no one changes behavior, no damage can have been done.

Before the leak, the terrorist placing a call to an American citizen knew that the call might be subject to monitoring pursuant to a warrant secretly issued by the FISA court.

After the leak, the terrorist knows that his call might be monitored as above and, in addition, that the call might be monitored without a warrant. Is the additional risk of warrant-less eavesdropping sufficient to cause the terrorist to change behavior?

Who knows? I doubt it but it might happen at the margin. Let's look at some possible ways the terrorists might change their behavior.

One way the terrorists might alter their behavior is by discontinuing the use of telephones and email for their communications. If they choose to do so, then the leak has denied the terrorists access to much of more than 100 years of technological advance in the area of communications. Surely, that would have a positive effect on national security. It seems unlikely that the terrorists would be willing to make that trade off, but, if they do, we need to balance the potential information that might have been gained by continued monitoring against the benefit of having the terrorists communicate like it is 1850.

It is far more likely that any change in terrorist communication techniques will be to change the way they use modern communication, not to give it up entirely. The terrorists may begin communicating with Americans only in code, or they may change the codes they already have.

Please note that the terrorists devised their communication system knowing that phone, email, and other electronic communications might be monitored pursuant to a FISA warrant. The additional risk of warrant-less monitoring does not seem large, and would change the terrorists' decision only if the initial decision was very, very close and the possibility of warrant-less monitoring was the straw that broke the camel's back.

The fact that it was a very close decision suggests that changing or initiating codes has costs to the terrorists. Those costs are benefits to our national security and deserve a place in the accounting.

The terrorists do not know which words or phrases trip the monitoring system. They can never be sure what triggers interest and what does not. It should be obvious that any additional time the terrorists spend worrying about the security of their communication instead of figuring out how to blow up Americans is a national security benefit.

A second way the terrorists might change their behavior is by sidelining some operatives while "waking up" sleeper cells to take the place of those "put to sleep." That could harm national security because we might then be watching the wrong people. It would also have benefits. I assume that everyone will agree that shutting down the activities of an American citizen in league with terrorists is a good thing. In addition, if the practice of putting current operatives "to sleep" is widespread, we get to play against the terrorists' second string. That might be a very good thing as I do not think they have a very deep bench in the United States.

Other possible harms can be envisioned. In each case, though, if it was easy for the terrorists to take additional precautions, they would have done so. Any change in the behavior of the terrorists will be at the margin. Because the changes of behavior will be at the margin, there will be benefits as well as costs to the terrorists being forced to change.

If we are going down the road of pursuing the leakers because of harm to national security, let's make sure we calculate the net effect.