[marshray]

Because The Guardian has 19,998 more documents that they don't know the contents of.

[discostrings]

If they have have acted properly, why should that stop them?

It's hard to lie effectively when you don't know how much of the truth is known.

[marshray]

Because nobody, probably not even at the NSA, is confident that they actually know the full extent of what's going on.

[discostrings]

So true. That's one of the most dangerous aspects of conducting this type of thing in the dark.