It's always nice to be vindicated. When grand jury testimony was leaked from the BALCO investigation, pointing to Barry Bonds and others using steroids or other performance enhancing drugs, lots of people (most vociferously, Bonds' defenders) assumed that it must be, had to be, the prosecutors doing the leaking. I never did a post here on the topic, but I did respond in comment threads when I saw this point made, arguing that it was at least as likely that the leaks were coming from defense lawyers rather than prosecutors. For example, in December 2004, Will Carroll wrote:

This "trial by leak" is something I'm very much against. In this case, the government has leaked its first significant broadside into what has been a very united front by Conte, Anderson, and others.

My response in the comments:

One thing I'd caution is that not all leaks come from the law enforcement side. It's illegal for prosecutors, FBI agents, etc. to leak grand jury testimony, which is secret (which is not the same as saying it doesn't happen), but not illegal for the witness or his lawyer (or someone to whom they gave the information) to disclose testimony. That seems wildly unlikely in Giambi's case, but there are often situations where a witness or codefendant has an interest in a leak, or where a defendant who is a political or other public figure prefers to leak things in drips at opportune times and spin them (while the prosecutor can't respond without disclosing other secrets) rather than face a sudden 'blockbuster' disclosure of the charge and the evidence all together.

My sense, though, is that many leaks in high-profile cases come from people lower down in the pecking order (court clerks, secretaries, word processors, etc.) who have less of an agenda and more personal or financial interest in handing sensitive information to reporters. Nothing happens in the law without a whole lot of people seeing it, and you can't watch all of them all the time.

I was too glib there about the law, by the way - a grand jury witness can only legally disclose the substance of his or her testimony, but can't, say, leak whole transcripts, at least not if they got them from the government. Obviously, my mind was heavily on Ken Starr's Lewinsky investigation of Bill Clinton - the leaks in that case almost invariably benefitted Clinton, allowing him to ride out each individual bit of the storm, where if the Starr Report had arrived out of the blue, it would have finished Clinton in one blow.

None of which is to say that prosecutors can't or don't misbehave with leaks - but it's always important to remember that there are just as often incentives to leak on the defense side as well.

In January 2005, CrimProfBlog argued that it had to be the prosecutors or the defense lawyers, and that it was unlikely to be the defense:

The defense attorneys and the defendants might have had an incentive to leak, since Bonds denied knowledge that the substances were steriods and said that he didn't think the BALCO defendant from whom he received the substances would have provided him with illegal steriods. It seems perhaps unlikely that one of the defense attorneys leaked the information, however, because leaking secret grand jury evidence to the media, and then moving to dismiss charges by blaming the government for the same leak, is a high risk venture that would take serious moxy if not insanity. Too much to lose, not enough to gain.

David Pinto linked to that analysis, to which I commented:

Well, except that taking risks and hoping they get away with being outrageous aren't exactly novel tactics for criminal defense attorneys.

While David kept his opinions to himself, others were not so shy - TalkLeft's Jeralyn Merritt, for example, asserted, "I rule out the defense."

Now, the truth is out: the leaks came from a defense lawyer for Victor Conte, who - get this - was devising a deliberate fraud on the court by leaking and then moving for dismissal of the charges on grounds of improper leaks, which his motion (including his own sworn false denial of being the source of the leaks) blamed on the government.

Hey, we can all be wrong, but I think this post is a good example of the crow that should be eaten by some of the more vociferous proponents of the "it has to be the government" theory.