Cooper talked to rove on "Double Super Secret Background" and it was directly tied to the story that he wrote.
Fitzgerald wants to know the contents of that conversation. While Rove is denying that he leaked the name, that isn't important. If Rove was involved in a conspiracy, talking to Cooper is an overt act. All that is required is an agreement to reach an illegal end. The email from Cooper to his publishers says to go to "a CIA source". Did Rove give Cooper that source? If so, then Rove could well be on the hook if he knew what that source was going to say.
It is my belief that Plame was first made as "chickenfeed" - trading of off the record information between reporters and sources - and not for the purpose of vengence, but before, when the White House was trying to establish a "Niger connection" for the "yellowcake" story.
It is likely that the WH planned a sting operation - Niger offers Saddam some illegal Uranium, and that would be used to prove that Saddam had nuclear weapons ambitions. In this line of reasoning, the scam would need a credible channel - the front company which Plame worked for would be that credible channel. When the scam fell through, Plame's name was floating around, and there was a story for the first person who was willing to go public with it.
The reason for all of the complexity then is that it is not clear when Plame's name first surfaced, and when a decision was made to burn Plame for reasons other than the original idea of lending credibility to another story.
Thus the sequence goes that CIA burned Plame's company to put the sting in the pipeline. When the sting falls apart, the "Iraq Group" - Rice, Rove, Rumsfeld being members - tried to have a "modified limited hang out" - use the failed sting as proof, bolstered by the "Italian Job" forged memos.
This is what ended up in the State of the Union Speech. When this falls apart - and the "16 words" are retracted, Plame's name, and the front company are lying around as expended assets. Worse still, they are assets which could be used to compromise the Niger story. Not because Plame knew anything, but because Plame did not know anything. That is, should anyone track down the front company, it would be found that there never was any Niger Yellowcake sale, and that any leads on Saddam buy Yellowcake had fallen through months before.
Thus Plame becomes a loose end, and is tied up by being burned. That Joe Wilson was busy exposing flaws in the Niger Connection made it doubly important - it would call him into question, and burn Plame as well.
Thus Plame's name is given to various reporters with the indirect approval of Rove and the White House. This is where Novak and Cooper come in, they are reporters that the White House gives the names of CIA sources to. What Fitzgerald is trying to prove then is that someone in the White House knew what those CIA sources would say. In this theory Rove didn't "lean the name" or even know the name, but he did hand out the name of the person who did.
- - -
But to get back on firmer ground: Newsweek reports that Rove is Cooper's Source X, that his conversation with Cooper may have lead to material in the article Cooper published, and that it certainly lead to actions taken by Time and Cooper to avoid detection of where the leak came from.
We are in the Oval Office.