The important thing to remember here is that the NSA was once started with noble goals in mind but it has since changed into an attack dog without much of a leash to hold it back. The NSA still has a useful function and indeed they'll compromise part of that function if their technical capabilities become too well known.

But to stonewall the general public on legitimate requests like these will cause people to use their fantasy as to what those capabilities really are, and that will likely overshoot reality. In that case any information the NSA is likely interested in will go underground so far that they won't be able to get at it in time to prevent damage.

On the other hand if they come clean and it will turn out to be (much) worse than people expected (and there is a good chance of this) then they will likely be reigned in diminishing their capability.

So they are damned either way.

Stonewalling is likely an indication that there is much more hidden than we know about today, otherwise coming clean would actually make them look better.

The best thing for the NSA would be for this whole thing to go away, organizations like that only work when they can do so in comparative secrecy. As soon as the spotlight is aimed at them some of their effectiveness (and in the case of the NSA likely quite a bit of it) will evaporate.

Those pesky foreign media and their relentless releases. Funny how the Guardian is the best place to get information about a United States institution, how Russian dissidents would move to the US and how a US whistleblower is now living in Russia.

It seems our (the general public) best chance in getting some progress in these matters is to play out nation states against each other.

I have no idea where this is all going but I could do with less surveillance in the name of (the war on) terror and a more constructive approach to geopolitical affairs to replace the 'might makes right' policy that we have today.