Defending a case like Lewis “Scooter” Libby’s is all about access to information. The problem is that much of it — including potentially exculpatory documents — is classified.

With that in mind, the former aide to Vice President Dick Cheney last week hired a San Francisco-based expert on classified documents to join the team of lawyers defending him on charges that he lied to a grand jury. That grand jury was investigating how CIA agent Valerie Plame’s name was leaked to the press in the lead-up to the Iraq war.