In a nutshell, what Ron Susskind says in his new book is that Bush/Cheney had George Tenet's CIA forge a document that purported to show Iraq had weapons of mass destruction. This document was then leaked to newspapers in London and used as a basis for the American invasion. He further states that MI6 and Tony Blair knew the contents of the document to be untrue.
It is pointless to argue the validity of what Susskind has written. Those dim witted stalwarts that still support the war, will say he lies. Those who have come to despise GWB and his unilateral foreign wars of aggression, don't need to be convinced of such a thing. Susskind's revelations simply validate already held assumptions, that Bush/Cheney lies at every turn.
The Bush administration, CIA and George Tenet are all busy issuing angry and outraged denials and vilifying Susskind. Tony and MI6 are saying nothing. Once again, doesn't prove a thing, except that even in corruption and decline the British have more class than GWB, even in his own imagination, even on his best day.