Julian Sanchez investigates the root of our anathematizing torture:
...as the research of folks like Joshua Greene and Jonathan Haidt shows, we have a set of evolved moral intuitions that are evolved to be especially keyed to harm to others that is both intentional and proximate. This (they suggest) is why many of us, in the classic ethics thought experiment, seem to think it would be acceptableeven obligatoryto switch a speeding trolley that is headed toward five people onto an alternate track where it will hit just one, but balk at saving the five by pushing an obese man into the path of the trolley. On this account, the discrepancy is just a side effect of the fact that our ancestors on the woodland savannah did not engage in many aerial bombing raids.
He goes on:
In war, we sometimes (and sometimes wrongly) accept the suffering that results from our actions because we cannot avoid it: suffering will be a side effect of actions aimed at concluding the war, but also of inaction that prolongs it, so we grimly tolerate its presence.
When we torture, suffering is the point; we cease to tolerate it an instead aim at it, make it our ally, hope to increase it beyond what the subject can endure. Bracketing a thousand other sound institutional and practical reasons not to make a policy of tortureand everyone should read Paul Campos’ summary of Rawls’ crucial insight on this scoreI find myself thinking that’s a difference that makes a difference. The first type of calculus might be tragic but right or horribly wrong; only the second is evil.