The defenders of torture in this country have illustrated a basic problem with human society. When you hear Dick Cheney say he did not care if innocent people are harmed, as long as the objective is reached, you are hearing that he does not care about the morality of our actions. But he and his supporters will claim they are the most moral of people. What they are really saying is that morality only applies to our own group (however defined at the moment). Morality is relative to the tribe, not to the whole human race.
The problem is that this viewpoint is the norm for most people through most of history. Many religious and philosophical thinkers have advocated a universal morality, morality that applies to everyone, but most people act otherwise. The American supporters of torture will mostly claim that they are Christians, and Christian morality as taught by Jesus is a universal morality. But their actions, or their support for torture, demonstrate otherwise. The bad guys are in the other tribe, the enemy tribe, and hence are all bad and must be crushed. To the torture supporters, anyone who we use such tactics against is by definition a terrorist. When the other tribe uses similar tactics against us, it just proves they are bad, because our tribe is the only one that counts.
When people say that it's ok to use "enhanced interrogation" (torture) against other people because the other people have done even worse things, they are doing the logical equivalent of a bank robber who says that what he did is ok since he is not as bad as the bank robber who shot the teller.
History has shown that this problem is a problem of human nature. So it will be very difficult to deal with. The starting point is to make people aware of the difference between universal and tribal morality and make it clear just what the choice is.