Tom Maguire of Just One Minute thinks that there isn't much to the agreement because the wording of Miller's subpoena referred only to Libby and her conversations with him. I view it differently. Questioning before the grand jury is not limited to documents specified in a subpoena.

For the non-lawyers among you, there are two kinds of subpoenas. One is called a subpoena and the other is called a subpoena duces tecum. A subpoena is for testimony and does not need to specify the topic, only the case in which the testimony is sought. A subpoena duces tecum is for the production of documents. In grand jury situations, a prosecutor will often forego the personal appearance and testimony of a witness if he or she complies with the production of documents in advance of the appearance date. For example, if the prosecutor is seeking cell phone records, the subpoena duces tecum will be issued to the custodian of records for the phone company. The phone company likely will be able avoid a personal appearance by sending the records to the prosecutor with an appropriate affidavit that these are the documents requested by the subpoena.

In other instances, like with the reporters in PlameGate, the prosecutor will want both the live testimony of the witness as well as the records. The documents are only part of what he is after from the witness.

With a subpoena duces tecum, there is no requirement that the prosecutor or grand jurors limit their questions to the subpoenaed documents. There are hurdles the prosecutor has to overcome before issuing subpoenas to reporters in the first place, as contained in the U.S. Attorneys' Manual, but once the subpoena has issued, and in Miller's case, upheld by a Court, all germane topics are fair game.

This grand jury is investigating the leak of the identification of Valerie Plame as a CIA operative and actions by White House officials in connection with it. Once subpoenaed, Fitzgerald (or the grand jurors)could ask Miller anything remotely connected to the investigation.

So, I think Fitzgerald's agreement to limit Miller's questioning to Libby is a big deal. It probably was far more a factor in her decision to testify than the release from Libby. No one ever bought her waiver argument - and she always was up front about not wanting to talk about her other sources.

As I wrote Friday night, there are some puzzling aspects to Libby's letter to her saying that he thought her testimony would help him. I'm not concerned, as are many commenters to Arianna's post at HuffPo that his statement about the Aspen trees turning is code between them. The last weekend of September is known in Colorado as being the aspen-turning weekend and they do turn in beautiful clusters. It's a big deal in the mountain states. Also, his comment about her liking to visit the mountains is probably true - she's a member of the Aspen Institute's Aspen Strategy Group.

I think Libby really did want Miller to talk...because he believed she would substantiate his claim that he did not reveal Valerie Plame's identity to her - or information about any concerted effort by the White House to do so - and that he did not disclose the contents of the June, 2003 State Department memo to her. Miller and Libby also had a 15 minute conversation the day she made up her mind to testify. Miller is no dummy. Wouldn't she have demanded an unmonitored phone for the call since jail conversations are recorded, except between clients and lawyers? Did Fitzgerald agree to this? If he did, then it seems like he wasn't afraid of collusion between them. Why not?

Back to the agreement between Fitzgerald and Miller. If Miller were to say she knew about Plame from another source, how could Fitzgerald agree not to question her about those sources? Wasn't his goal to find the leakers? Isn't he giving up that chance by agreeing to limit the questions to Libby? What if she talked to Cheney, Rove, Bolton, Hannah or Hadley about it, or to anyone in the White House Iraq Group? He'll never know. But maybe he doesn't care, because he is no longer investigating who leaked, only who lied.

If Miller, like Matthew Cooper and others, says she discussed Joseph Wilson's wife with Libby and her role in sending Wilson on the uranium mission, but that Libby never told her the wife's name or position with the CIA, does that put Libby in the clear? Maybe, if that's also what he consistently told investigators and the grand jury -- and if his and Miller's notes and his emails back that up.

Fitzgerald told the Court that Judith Miller was the last link to his investigation. His lack of interest in her other sources may indicate that he's concluded the leaking of Plame's identity as "Joseph Wilson's wife" but not by name or CIA function, is not a crime. I would agree with that. For a long time now, the issue to me has seemed more to be about a cover-up, perjury and obstruction of justice.

The fact that Fitzgerald told the Judge early this month that Judith Miller's testimony was essential to the successful conclusion of the investigation indicates that this investigation has moved far past the stage of who outed Valerie Plame and whether she was or was not a covert operative and on to whether White House officials and/or reporters lied in their initial interviews with grand jury investigators or during their grand jury testimony - and whether there was an attempted cover-up that would amount to a conspiracy to obstruct justice.

...On November 18, 2004, the AP reported that Fitzgerald told the Judge Matthew Cooper's second subpoena (after the first about Lewis Libby with which he complied) was necessary because he needed more information from Cooper "due to an "unanticipated shift" in the grand jury's investigation." (available on lexis.com)

The "shift" can only be away from the identity of who leaked Valerie Plame's identity into a broader investigation into perjury, obstruction of justice and conspiracy to commit both.

I still think all roads lead back to the White House Iraq Group and the concerted effort to discredit Joseph Wilson. As the UPI reported on Feb. 5, 2004:

On June 12, Washington Post reporter Walter Pincus revealed that an unnamed diplomat had "given a negative report" on the claim and then, on July 6, as the Bush administration was widely accused of manipulating intelligence to get American public opinion behind a war with Iraq, Wilson published an op-ed piece in the Post in which he accused the Bush administration of "misrepresenting the facts." His piece also asked, "What else are they lying about?"

According to one administration official, "The White House was really pissed, and began to contact six journalists in order to plant stories to discredit Wilson," according to the New York Times and other accounts.

One of the planted stories was that Joseph Wilson's wife, who worked for the CIA, was responsible for sending him to Africa to check on the uranium claim. New York Times reporters David Johnston and Richard Stevenson wrote on April 3, 2004:

Mr. Fitzgerald is said by lawyers involved in the case and government officials to be examining possible discrepancies between documents he has gathered and statements made by current or former White House officials during a three-month preliminary investigation last fall by the F.B.I. and the Justice Department. Some officials spoke to F.B.I. agents with their lawyers present; others met informally with agents in their offices and even at bars near the White House.

....The suspicion that someone may have lied to investigators is based on contradictions between statements by various witnesses in F.B.I. interviews, the lawyers and officials said. The conflicts are said to be buttressed by documents, including memos, e-mail messages and phone records turned over by the White House.

At the same time, Mr. Fitzgerald is said to be investigating whether the disclosure of Ms. Plame's identity came after someone discovered her name among classified documents circulating at the upper echelons of the White House. It could be a crime to disclose information from such a document, although such violations are rarely prosecuted.

Maybe Fitzgerald just wanted assurances from Judith Miller that when she and Libby met on July 8, Libby never showed her or disclosed information contained in the classified document that identified Plame by name, the one that made its way on July 7 onto Air Force One.

It's possible there will be no indictments in this case. But, my instincts tell me there will be, and they will relate to perjury and making a false statement to a federal official, or a conspiracy of some sort, rather than to the actual leak of Valerie Plame's identity. Maybe Cheney will be one of those caught in a false statements or conspiracy charge. Since he's considered the most powerful man in Washington, it's unlikely. His staff, and the White House Iraq Group, however, may not fare so well. And Rove's biggest liability may be his story that he first heard of Plame from a reporter, but he can't remember which one, and that his call to Matt Cooper was initially about welfare reform. That's about as convincing as a drug dealer who agrees to cooperate and then says he can't remember who sold him the kilo of coke.

Update: Pincus and VandeHei of The Washington Post today reports on new support for the criminal conspiracy theory, coming from lawyers for witnesses who have talked to Fitzgerald:

But a new theory about Fitzgerald's aim has emerged in recent weeks from two lawyers who have had extensive conversations with the prosecutor while representing witnesses in the case. They surmise that Fitzgerald is considering whether he can bring charges of a criminal conspiracy perpetrated by a group of senior Bush administration officials. Under this legal tactic, Fitzgerald would attempt to establish that at least two or more officials agreed to take affirmative steps to discredit and retaliate against Wilson and leak sensitive government information about his wife. To prove a criminal conspiracy, the actions need not have been criminal, but conspirators must have had a criminal purpose.

Update: There seems to be some confusion about Ms. Miller's agreement. Adam Liptak reported in the Times:

The second factor in Ms. Miller's decision to go before the grand jury was a change in the position of the special prosecutor, Mr. Fitzgerald, concerning the scope of the questions she would be asked, according to Mr. Abrams. Mr. Fitzgerald only recently agreed to confine his questions to Ms. Miller's conversations with Mr. Libby concerning the identification of Ms. Wilson, Mr. Abrams said.

Also, Abrams said the notes she turned over "were redacted to omit everything but the notes taken concerning discussions with Libby about Plame."

Johnston and Stevenson report in the Times:

Ms. Miller and her lawyers said she had agreed to testify because her source had released her from any pledge of confidentiality and because she had received a guarantee from the prosecutor in the case that he would restrict his questions to that one source.

And Judith Miller said outside court:

Once I got a personal, voluntary waiver my lawyer, Mr. Bennett, approached the special counsel to see if my grand jury testimony could be limited to the communications with the source from whom I had received that personal and voluntary waiver. The special counsel agreed to this and that was very important to me.