Talking Points Memo has an interesting backgrounder on the Plame investigation. It looks like Valerie Plame was potentially exposed as a secret agent twice in the past, mostly thanks to Aldrich Ames (the counter-spy). It is starting to look like the White House is going to use this information to muddy the prosecutorial waters around the Novak article, probably in an attempt to keep "Scooter" Libby out of prison.
There does seem to be a rush of articles aimed not simply at discrediting Wilson but specifically at arguing that there is no legal basis for a prosecution of the folks who leaked Plame's name. Who's so concerned? It makes me wonder.
If this succeeds, then it will set a precedent for weaseling out of breaking the law by discrediting a political enemy.