I only would depart from your position to suggest that the plot originated with Plame and Wilson together. They are, after all, husband and wife, and both of them appear to be flaming liberals who hate Bush.
My question has been, why did the CIA allow Plame to get away with it? Who approved giving the assignment to Wilson? Or did Plame do it all on her own?
Tenet was still director. Did he know about this beforehand? It was, after all, a critical mission at the time, because it was in an area touching on the administration's highest priorities. It must have been evident that a screwup, accidental or intentional, could blow up in everyone's face.
the cia has its liberal components too.