I became interested in the history of code breaking and surveillance in the late 1970s, even before The Puzzle Palace permanently breached the NSA's public anonymity.
I don't get the public furor because there's nothing new here: what Snowden revealed is just a logical extension of how this program has always operated, as documented since way back for anyone who wanted to know. It has always been part of the anonymity construct that the NSA could purport (or purport by implication) that it operated within the groove of democratic principles, up to a point. The old relationship with the British (I'll watch yours, if you watch mine) was always a burden, but I guess that burden must have been manageable for a time.
Once COTS technology (Cisco, Nortel, Lucent, Alcatel, Juniper) begins to outpace the astrobuck edge, the NSA is forced by brutal practicalities to review and revise their anonymity construct. Just how much can be exchanged through a stiff-upper-lip tea service?
At this point, the NSA's democratic cloak is outright risible: any foreign person, anyone whose patterns of contact with such people is vaguely suspicious (there has never been a shortage of suspicion where suspicion greases operational desires) and anyone who crosses paths in any way with this substantial kernel of the vaguely suspicious, citizenship be damned. We're more than halfway along the spectrum of seven degrees.
Suppose we apply the principles of differential cryptanalysis to this interesting social network. Suppose there is some American citizen not yet trawled by this social graph of chance connection. What's the least amount of suspicion one must inject at some chosen suspicion-coloured node of this graph for a tentacle to slop out of the bucket to engulf the arbitrary citizen of the moment? Once engulfed, does this person ever escape this webbing ever again on principles of liberty and freedom or is this person's only democratic salvation to fall beneath some metric of cost/benefit in keeping his or her node active in the vast suspicion graph? How much easier is it for a person to be bumped back into this mesh once you've been on it before? Does that scarlet letter ever fall off?
I doubt there's anyone in America whose nose is so clean that ten minutes of brow-drenched pretext-manufacture by some nearby NSA staffer with any prospect of future promotion wouldn't serve to lasso this person onto the suspicion list by some ready-to-hand agency criterion (a clean nose for this purpose is mainly established by not getting out much except on Sunday morning, not using email, and never answering your telephone when pestered by a wrong number).
That's pretty much the minimal operation capability they would settle for, no matter which democratic cover story of the day hits the news cycle. I doubt they ever expected that a program as large as this could maintain cover of darkness indefinitely. So the real response and public optics is mainly for consumption inside the Faraday cage: the Snowden meme is not one they wish to see take root among their own.
It's a basic tenant of military or police training to punish the group on the pretext of individual lapses, failure, or sloth until the group is conditioned to self police. Wouldn't be surprised if everyone in the entire agency is working unpaid overtime on invented files (as in The Firm) until Snowden is brought to Faraday justice. I get the internal furor loud and clear.