"It's all OK because there were backup copies.
"As NSC advisor, Berger knew that there were backup copies, so that's what made it OK for him to take them."
As a NSC advisor, Berger, also knew that if anyone with a clearance to see what he took, put them in our pants and got caught, we would have gone to jail for a long time. Copies carry the same security clearances/restrictions as the original documents.
Also, Berger was not the NSA chief, they probably wouldn't have let him on the parking lot that they don't have.
affectionately known as "big daddy."