It's my understanding that at least some legal cases on the subject are hobbled by a lack of official evidence that such surveillance is under way. ("You can't prove that we're doing it, because all the documents are secret. The court thinks so too. Come back when you have proof.")

Assuming that this document is real, perhaps it may provide sufficient leverage to force into the light whatever hides in the shadows. At least some of those who might authorize such a program will be earnest in intent; we would be wise to carefully consider their justification.