Because we are fighting stateless, unlawful combatants. Iraq I, Vietnam, Korea, WWII were all fought against nation states. That's the difference. Detainees in the WOT are not entitled to Geneva convention protections. Furthermore, it's not like the Geneva convention helped McPain avoid torture in Vietnam.
The Supreme Court ruled differently. And if we water down Geneva Convention, it will apply to detainees from states as well as stateless. A bad idea all round. I grew up on movies like "Stalag 17," which made a point of showing it was the Krauts who violated international accords on prisoners by, for example, keeping men standing long periods and interrogating them without giving them sleep. Billy Wilder (director of Stalag 17) seemed to think this verged on torture (that was the clear implication in the movie), but now has it become acceptable practice in the US military and CIA? That's not progress, in my opinion.
My question regarding torture and McCain is "did McCain talk?" So then, did the torture work contrary to the claims being made that torture doesn't work?