Isikoff Scoop on Armitage and Plamegate

It's long been suspected that ex-Deputy SecState Richard Armitage was Bob Novak's first source for his column outing Valerie Plame -- the source whom Novak described as "no partisan gunslinger." Now Michael Isikoff has a blockbuster preview of his new book in which several sources confirm as much:

Armitage, a well-known gossip who loves to dish and receive juicy tidbits about Washington characters, apparently hadn't thought through the possible implications of telling Novak about Plame's identity. "I'm afraid I may be the guy that caused this whole thing," he later told Carl Ford Jr., State's intelligence chief.

A few thoughts:

1. It is simply amazing that this news has held as long as it has. Isikoff writes that Colin Powell, Armitage and Carl Ford were the only people who knew of Armitage's role. Does that make them somewhat culpable, from a PR or a legal perspective?
   
   
2. Does Armitage currently have a PR person on retainer to help him plot through his next steps. This certainly qualifies as a "crisis communications" moment.
   
   
3. Isikoff mentions that his new book, from which this news is adapted, is coauthored with David Corn, a prominent liberal and Washington editor of The Nation. Will the fact that Iskikoff's coauthor has a partisan ax to grind minimize the impact of his scoop? Will it make it easier for the RNC and White House to dismiss the report, and the book?

Other thoughts on the Isikoff scoop?