Maybe a freeper lawyer can clear something up for me - - why wouldn't Libby's lawyers already have this tape of a conversation between a reporter and a government official? Clearly, the tape is relevant and crucial to the defense, and obviously there is no threat to national security.
I'm not a lawyer, but what do you mean by "already have the tape"? Do you mean the Washington Post should have given them a copy just like they gave to the Prosecutor, or do you mean the Prosecutor should have given it to the Defense without it having to be subpoenaed?
You are correct in your belief that the prosecution is obligated to turn over all relevant evidence in its possession to the defense and that a subpoena is not normally necessary. My guess is that Fitzgerald is taking the position that the Woodward/Armitage tape is not relevant. That is because Scooter is not charged with illegally leaking Plame's name but rather with lying to investigators. Technically Fitzgerald may have a point, but he knows the judge won't be sympathetic, so he has probably said to Scooter's lawyers, "I won't give it to you voluntarily, but if you subpoena it, I'll comply with the subpoena." It's a face-saving device.