‘For ten years, if not more,’ declared the Old Bolshevik Kamenev to the Moscow court in 1936, ‘I waged a struggle against the Party, against the government of the land of Soviets, and against Stalin personally.’

That preposterous confession was wrung from one of Lenin’s closest allies  by pretty much the same methods detailed in the select committee’s report: sleep deprivation, isolation, threats against loved ones and so on. It’s not very far from the hallucinatory testimony at the Moscow Trials to the descriptions of Abu Zubaydah as such a broken shell that the interrogator needed only to raise his eyebrows to make the detainee shuffle over and lie down on the waiting waterboard.

Even though you can, quite probably, obtain information via stress positions and simulated drownings (at least under certain circumstances), torture’s mostly about power rather than knowledge. From the Spanish Inquisition to Stalin’s Russia, interrogators have used to pain to produce not facts but confessions, a ritualized acknowledgement by the detainee of the regime’s power.