nope nope
the object is not to fight as dirty as possible, the object is to fight as smart as possible.
"Smart" would be part of "effective." Here's a question for you. Answer which you think is "smart":
You have a group -- say 10 -- high value AQ terrorists in custody. They are non-uniformed combatants, so the Geneva Convention does not apply. They have critical information. Do you (1) waterboard them, knowing you will get that information and probably a bunch of garbage information out of them, but also knowing you'll be able to correlate the good information from them with a fairly high degree of confidence, or (2) treat them with kid gloves knowing that they will see this as a sign of weakness?
(1) will lead to a shorter war and less deaths on both sides. (2) will lead to a longer war, more deaths on both sides, and as we saw repeatedly in Iraq, more horrors visited on our own troops by other AQ terrorists who see us as weak.
I submit that (1) is clearly smarter and in the long term more ethical. All (2) does is let people feel that "we're not as bad as them" -- feel more ethical -- while reaping more deaths and horrors as an unintended consequence. The only real advantage of (2) is it makes the war more "acceptable" to both the armchair populace back home AND the AQ enemy. Those are BAD things.
By the way, (1) is the option chosen by the people whose job it is to fight and win our wars. I think they just might have a clue about what they're doing...