Those who do not remember the past, yadda yadda yadda. Will Durant reminds us what war was like in the Assyrian army, in the 18th-7th centuries BC:
The loyalty of the troops was secured by dividing a large part of the spoils among them; their bravery was ensured by the general rule of the Near East that all captives in war might be enslaved or slain. Soldiers were rewarded for every severed head they brought in from the field, so that the aftermath of a victory generally witnessed the wholesale decapitation of fallen foes. Most often the prisoners, who would have consumed much food in a long campaign, and would have constituted a danger and nuisance in the rear, were despatched after the battle; they knelt with their backs to their captors , who beat their heads in with clubs, or cut them off with cutlasses. Scribes stood by to count the number of prisoners taken and killed by each soldier, and apportioned the booty accordingly; the king, if time permitted, presided at the slaughter. The nobles among the defeated were given more special treatment: their ears, noses, hands and feet were sliced off, or they were thrown from high towers, or they and their children were beheaded, or flayed alive, or roasted over a slow fire. No compunction seems to have been felt at this waste of human life; the birth rate would soon make up for it, and meanwhile it relieved the pressure of population upon the means of subsistence. Probably it was in part by their reputation for mercy to prisoners of war that Alexander and C???sar undermined the morale of the enemy, and conquered the Mediterranean world.
— Will Durant, The Story of Civilization, vol. 1, Our Oriental Heritage, p. 271
Vindictive right-wing idiots notwithstanding, I think it’s pretty clear how this applies to current US policy in Iraq: if the enemy knows that if he surrenders, he’ll be either executed or tortured, then he has a pretty powerful incentive to fight like a sumbitch and take down as many of our guys as possible. If, on the other hand, it’s known that Americans treat prisoners of war humanely, then hey, maybe surrender doesn’t look quite so bad.
So even setting moral considerations aside, it makes good strategic sense not to provide enemy combatants with an incentive to fight to the last breath, by treating prisoners humanely. No one’s saying that a stay at Gitmo is, or should be, like a weekend at the Hyatt. But it should be preferable to shooting at our troops.
And I still can’t believe there’s any kind of debate on this, why “no torture as a matter of national policy” isn’t a no-brainer.