It's called "Greymail".
It was first used back in the early 1980s, IIRC, as part of a criminal's defense. He threatened to defend himself on the stand by revealing certain goobermint secrets.
The courts ruled that a defendant could not publically expose confidential material in public, so closed trials were ordered and the transcripts edited or sealed.
Thanks for the term, 'Greymail'.
It looks like there are ways to get to Berger without jeopardizing confidential material. Check out the video.
I read that some of the papers that Berger burglared pertained to the Millenium Bombing plot which was still under appeal. This would fit with your theory of greymail.
So, why hasn't the Bush Justice Department still not given Burglar a 'lie Detector test". Your "Greymail' theory looks good on paper. However, why would that prevent the Bush justice department from giving Burglar a "lie detector test" as was agreed in his plea bargain?