I think the Detainee Treatment Act engages the standard under the Constitution, which is a "shocks the conscience" standard, which is essentially a balancing test of the value of doing something against the cost of doing it... the heinousness of doing it, the cruelty of doing it, balanced against the value. Hypothetically, getting some historical information that wouldn't save lives, you wouldn't have to reach the question of whether it's torture or not. It shocks the conscience.
Um, all torture shocks my conscience, dude.
It really pisses me off when people use completely irrelevant situations to justify awful things, like torture and the death penalty. "Well what if you were totally sure the prisoner did all these bad things? What if you were certain that he knew where the nuclear bomb was, then wouldn't it be worth it to torture him?"
NO, people! First off, if a guy tells me he knows where a nuclear bomb is, I don't think I should trust him. I'd wonder who he's covering for. Second, if we all just strongly suspect that he knows, I don't think that's enough justification to torture someone. Even if I did think torture was morally okay, I still wouldn't trust anything anyone said to me while being tortured. You could torture me into saying all kinds of things, it doesn't mean any of it would be true, I'd just want you to leave me alone.
So we make ourselves morally despicable, for what? Because it makes us feel tougher? Makes Americans feel safer from terrorists?
To me, saying "Isn't torture okay, if it's saving lives?" is like asking "Is it okay to run over small animals, if it prevents earthquakes?" STOP.