Beyond the moral and criminal grounds for being opposed to torture, former top military commanders give a purely utilitarian reason: it degrades our efforts to win.
The torture methods that Tenet defends have nurtured the recuperative power of the enemy. This war will be won or lost not on the battlefield but in the minds of potential supporters who have not yet thrown in their lot with the enemy. If we forfeit our values by signaling that they are negotiable in situations of grave or imminent danger, we drive those undecideds into the arms of the enemy. This way lies defeat, and we are well down the road to it.