NRO's Yuval Levin poses an apt question:
Doesn’t it seem like Obama and his supporters in the press are over-learning the Swift Boat lesson with their reaction to the Corsi book? Kerry’s original instinct in 2004 was to ignore the attack so as not to draw more attention to it. The substance of it turned out to be too powerful for that to work, and he realized that only after it had gone on too long. But the substance this time is rather different: the book may well be full of charges of various sorts, but it won’t be anything like people from Obama’s past offering evidence that explodes the essential storyline of his campaign. Wouldn’t the Kerry reaction be more politically astute here? Doesn’t the “answer every charge so you won’t be swiftboated” principle get the book a whole lot more attention than it would otherwise get without really preventing or averting much real harm?
On balance I'd say Corsi probably warrants the pushback he's getting. Still, The hype level--fueled, in part, by the Obama camp's engagement--is striking for a book frequently sourced to random bloggers.
Update: Eh, maybe Levin's not onto something. As Ben Smith notes, it was only after the Corsi book was on the front page of the Times that the Obama team really engaged. It seems that as long as it was mostly conservative book-club readers seeing the book they were content to ignore it.