This week, Bob Woodward didn’t break a story. He entered the story. On Wednesday, The Washington Post, Woodward’s home base, disclosed that two days earlier the nation’s most prominent reporter had given a sworn deposition to special counsel Patrick Fitzgerald. According to a statement issued by Woodward, the week after Fitzgerald indicted Scooter Libby, Fitzgerald asked Woodward to come in for a chat–under oath. What had happened was that a senior administration official had recently revealed to Fitzgerald that in mid-June 2003–a month before conservative columnist Bob Novak published the administration leak that outed Valerie Wilson as an undercover CIA official–this Bush official had told Woodward that Valerie Wilson worked for the CIA as a WMD analyst. (The official apparently has not permitted Woodward to disclose his or her name publicly.) This revelation changes the chronology of the leak case. Previously, Libby’s June 23, 2003 conversation with New York Times reporter Judith Miller was the first known instance of a Bush administration official telling a reporter about former ambassador Joseph Wilson’s wife and her employment at the CIA. Now, it turns out, another top administration figure shared this classified information with Woodward a week or so earlier.

Yet another round of Plamegate guessing has exploded. Who wasWoodward’s source? Was this person Novak’s original source? (As of now, only the second of Novak’s two sources–Karl Rove–has been fingered.) Why did Woodward sit on this information and not even tell the editor of his paper about this conversation until late last month? (Woodward has apologized to Post executive editor Len Downie Jr.) Did Woodward’s possession of this inside information prompt him to criticize the leak investigation repeatedly on talk shows? Was he putting down Fitzgerald to protect or curry favor with one of his insider sources? Will this have any impact on the case against Libby?

As for the big who-is-it question, no sooner had the speculating begun that several obvious suspects denied being Woodward’s source. An unnamed administration official quickly told The New York Times that neither Bush, White House chief of staff Andrew Card Jr, nor White House aide Dan Bartlett had spilled this secret to Woodward. Spokespeople for Colin Powell, former CIA chief George Tenet and former CIA director John McLaughlin did the same. (By the way, how can an administration official issue such a denial when the White House position is that it will not comment on the leak case while the investigation remains open?) A lawyer for Rove said that Rove was not the one. (Rove only talked about Wilson’s wife with Novak–supposedly as Novak’s second source–and Time‘s Matt Cooper.) As the Times noted–slyly?–“Mr. Cheney did not join the parade of denials.” Nor, it seemed, did Richard Armitage, who was deputy secretary of state under Powell.

After these denials came out, a smart columnist called me and asked isn’t it now clear the available evidence indicates that Cheney, who was previously interviewed by Fitzgerald, was Woodward’s source and that Libby had lied to prevent Cheney from being charged with perjury. Not necessarily, I replied. It’s worth noting that, according to the Libby indictment, when Cheney told Libby on June 12, 2003, that Wilson’s wife was in the CIA, he said she worked at the Counterproliferation Division, which is part of directorate of operations (aka the DO), the clandestine portion of the CIA. Woodward claims that his source described her as a WMD analyst. The difference in the terminology might be significant. Then again, it might not be. It’s also hard to imagine Cheney approaching Fitzgerald and conceding anything, even if he was worried about Libby flipping (and there have been signs of that). But if Cheney–who had been collecting information on Wilson’s wife apart from what Libby was doing–did tell a reporterabout Valerie Wilson (particularly after finding out she worked in the DO, where most employees are undercover), that would be a rather dramatic shift in the leak saga. [UPDATE: On Thursday night, the Associated Press reported that a “person familiar with the investigation” said that Cheney was not Woodward’s source. Richard Armitage, look out. CNN is reporting that a spokesperson for Armitage said “no comment” when asked if Armitage was Woodward’s source–which makes Armitage the only person on the Official Speculation List who has not yet denied it.