How do you convince someone in a militant mindset that privacy in wartime is a good idea? Appealing to ethics is irrelevant, as a militant mind will always justify means by their ends.
So if we want to stop telco immunity, and the loss of privacy in a country supposedly of the free, we can't focus on the "for the common good" aspects - we have to prove that the ends aren't useful anyway.
The problem is not how to show that eavsdropping, in this case, on phone calls will not yield useful information. In fact, it probably does (albeit in really rare and lucky circumstances). The problem should be more of a practical one: resources spent mass-collecting and auto-mining conversations of citizens should be better spent in other ways, like maybe good old fashion police work and detective work.
Unfortunately, we're not privvy to the "success" rate of the program, if there even have been any successes.
Can anyone think of a way to argue for the uselessness of this process in a way that does not appeal to ethics?