Since 2001 (when he arrested) NSA and surveillance technology has gone through a radical change. Society has also changed radically for the time Robert Hanssen was recruited into intelligence service, and the time Snowden started to work for the NSA. The scrutiny that existed for new employees in 1976 is nowhere similar to 2006.
I'm baffled by how you can simultaneously hold these two thoughts in your head --- that NSA surveillance has improved so much that it's impossible for foreign governments to plant moles in the giant NSA org chat, but that it's so bad a random kid can download gigs of documents to ship off to Glenn Greenwald.
It is a very hard (and well known) security design problem to make system that the system builders and maintainers themselves can't access. Its possible, but few do it even today.
Russia intelligence is an external threat, and its threat model is well know. Whistleblowers are an internal one.
So to me, its not difficult at all to see why external well know threats are today less likely to happen, while new internal ones are missed. I have the same view of Windows security, in that Russian hacker has a hard time to break in, but a Microsoft employee would have a much easier time.
Different threat models. I assume you are well familiar with the concept so I am a bit baffled by your baffledness.
side note: After they identified Robert Hanssen as a rouge entity, were the NSA unable to provide evidence after the fact? This is after all the question I originally made.
Back in 76 there would have not been contractors (who had been let go by the CIA) employed by a third party working inside the NSA - which is where the vetting fell down
Sure, and the scrutiny in 1976 was vastly improved to 1956, or twenty years before that, etc. As the saying goes, espionnage is one of the world's oldest professions.
If there wasn't a real fear of long-term moles in government, counter-intelligence wouldn't be such a huge part of what the Intelligence Community does.
Presumably the fact that Snowden took what he did and yet they still have no idea what he did take is ample evidence that the emperor is wearing no clothes and anybody could have anything by now. The security crime here was to aggregate all that info because this was an entirely inevitable outcome.
