DeLong contrasts Bush's description of Abu Zubaydah with Don (One Percent Doctrine) Suskind's description. Briefly, Bush claims Zubaydah was a senior terrorist leader and that much value was gained from torturing him (ok, Bush doesn't use the word torture, instead he lies). Suskind says Zubaydah was mentally ill and was tortured because his captors were ... ummm .... nuts.
What makes this contrast plausible to me, beyond Bush's record of staggering incompetence and seeming organic brain disorders, is the right wing's rejection of the concept of mental illness. It's almost a pathognomonic feature of cultural conservatives that, for them, mental illness doesn't really exist, that it cannot affect judgment or decisions, and that delusions are fundamentally a form of deliberate deception. Medieval inquistors of witches shared a common value set, as do modern Scientologists.
It's easy to believe that Bush and his ilk, confronted with a mentally ill terrorist, would believe he was being deceptive, and would think torture would produce truth.