Guessing at the torturer's rationale: is efficiency key?

This Yglesias post inspired a thought:

It’s shocking how easy it is to be shocked all over again by browsing through Jay Bybee’s memo. For example: “These procedures, as discussed above, involve the use of muscle fatigue to encourage cooperation and do not themselves constitute the infliction of severe physical pain or suffering.”

It’s not pain, it’s just muscle fatigue. And it’s not severe. It’s just bad enough to compel you to cooperate.

For those torture apologist that don't think that the President can order anything, the guiding idea seems to be that the problem with traditional torture is that it is inefficient in terms of pain suffered and damage done.  Thus it becomes a twisted version of a medical problem.  How can you break someone while not causing irreversible physical harm or pain above a certain magnitude.  They don't seem to get that breaking someone's spirit is inherently problematic.  As I understand it, more effective techniques involve time, gaining trust, and of course some level of psychological manipulation.  Coercive techniques basically rely on the victim being willing to tell you anything to get you to stop.  And since they'll tell you anything, you'll get a lot of bad intel that you want to believe since they're saying what you want to hear.

Also as a quick clarification on my prior post.  Torture is illegal under domestic U.S. law whereas the Supreme Court, and not just an executive branch lawyer has upheld the legality of abortion and the death penalty.  At the same time, torture is illegal under international law.  That would provide an alternate basis for prosecution.  However, there's no relevant treaties that we've signed on to (there might be something out there on the juvenile death penalty).  So the situation that Saletan describes wouldn't come up under either domestic or international law.  [Update: One possible exception, there was a big fight over the executions of Mexican nationals that didn't get to contact their embassy.  That wasn't specifically about the death penalty, but was relevant to international law.  However, that's about due process and not outcomes.]