Whatever is in those documents is more damaging than the consequences for first claiming they had no involvement then proving/admitting their involvement by exerting executive privilege.
Just as with Sandy Burglar, the information in the documents was worse than the consequences for stealing them.
Maybe the White Crib documents will prove that Mr. Soetoro lied to the President of Mexico about the whole stinky mess. Maybe that is the the White Crib's "national security" clam-up.