That is alleged in the indictment. It is a necessary fact to support the allegation that Libby lied to the GJ.
And if he truly believes that assumption is true, he could have charged Wilson with the leaking of classified information and presented his case.
The indictment does not allege that the information leaked was classified. The indictment only alleges that Libby was not truthful in his testimony to the GJ.
What if Libby just used the "My recollection is not clear" to Fitz's questions in the GJ? Then what would have Fitz done. Wrap up the case, no indictments, and call it a day?
If there was no evidence that Libby lied to the GJ, this indictment would not have come down. And Fitz would have had to find a violation of 50 USC 421 (outing covert agent) or 18 USC 793 (not likely); or quietly disband with the conclusion that he found no violation.
" If there was no evidence that Libby lied to the GJ, this indictment would not have come down" We'll have to see how strong that evidence is, when (and if) we hear the other side of the case. Allegations sound strong when you only hear one side.