re: Revenge
Whatever other arguments might be brought into this, the idea that if we can expect better treatment of our prisoners if we treat al Qaeda prisoners better is a complete load of crap.
With rare exceptions our troops in war haven't been treated according to the Geneva accords by our enemies in two generations. Our current enemies aren't even fighting according to the Geneva conventions. They have violated every single prohibition.
Make whatever other arguments you want, but drop that one. It has no basis in reality.