The liberal establishment is having a collective orgasm over this book. Coming out when it has they believe it will put the exclamation point on a resounding Democrat victory in November. That, combined with the Foley debacle, is a one, two punch from which the Republicans will not recover (nor will the media let them).
This book will have absolutely no effect on the election. It joins the other 15000 Bush bashing books. You can only cry wolf so many times. People have decided about this issue long ago.
The Foley stuff will hurt however.