It is the lynchpin of the legal case for prosecuting the war criminals of the last administration. We have known for a while that the Justice Department's old guard was going to protect itself and even those who violated basic norms of legality and morality within it. We have known for a while that president Obama and attorney-general Eric Holder have decided to remain in breach of the Geneva Conventions and be complicit themselves in covering up the war crimes of their predecessors - which means, of course, that those of us who fought for Obama's election precisely because we wanted a return to the rule of law were conned.

Whether this betrayal is a prudential and reluctant attempt to play a long game, to avoid, Lincoln-like, a deeply divisive and explosive political war for the sake of the country; or whether it is a cynical and Clintonian form of rank and cowardly opportunism (yes, Rahm, we know who you are), will surely become clearer in due course. I certainly hope the former. I believe the president knows what occurred, and his repeated public use of the word "torture" for the policies of his predecessors is a way of telling the world and future prosecutors in the US or around the world what Cheney and his team did. For the record. Deep down, I still trust him on this, in what is an awful and potentially explosive situation.

Holder has restricted the investigation of the Cheney era war crimes to those that went beyond the torture "legally" allowed by the OLC memos. But it remains possible that once you start pulling on that thread, any serious legal investigation will find it impossible to make such absurd and semantic distinctions when the guiding laws and treaties are so abundantly clear that such distinctions are absurd.