We know for sure that Dick Cheney and his crew were obsessed with proving some sort of link between Iraq and Al Qaeda. That was their golden key to provoking the nation into war. But there now seems to be some evidence that Cheney pushed for torture in order to prove this - and not, as he has said, to get actionable intelligence on imminent terror threats (not that that would excuse breaking the law either).
And look, I know all these roads seem to lead to Dick Cheney, but Dick Cheney was the vice president. The buck on all of this lays at the feet of George W. Bush.