new CIA leak: who and why?

So, as we all know by now, the info about the eastern-European 'black site' prisons most likely orginated from a discussion at a GOP-only Senate luncheon attended by Dick Cheney.

But who at the event would be motivated to go to the press with that info, and what are possible motivations.

Was someone trying to demonstrate the administration 'toughness' on terror?

Or has someone had enough kool-aid, and called the adminstation on their latest immoral activity?

It looks like the CIA has gone to the DoJ to investigate the  leak: CIA Moves Toward Probe of Prisons Story

I think the source is probably going to be protected, and that sounds about right.  An honest source giving truthful information to a journalist deserves protection.

But the bigger question to me is why this info came out at this time?